Lindsay

This page lists questions and answers that were posted by visitors named Lindsay.

Questions

The following questions were asked by visitors named Lindsay.

Given that the distancef rom Earth to the Moon is 3.8 x 10^8 m, that the Moon takes 27 days to orbit Earth, and that the mass of the Moon is 7.4 x 10^22 kg, what is the acceleration of the Moon and the size of the attractive force between Earth and Moon?...

19 years ago

Recall that on some roads, a skid mark of length L ft. indicates that a car was traveling at least s mph, where s is approx. 2 times the square root of 5L. If a car stopped quickly from a speed of 55 mph, about how long would the skid marks be? Please not...

18 years ago

Icebergs in the North Atlantic present hazards to shipping, causing the length of shipping routes to increase by about 30 percent during the iceberg season. Attempts to destroy icebergs include planting explosives, bombing, torpedoing, shelling, ramming,...

18 years ago

It would be great if, again, someone would check these answers for accuracy. I'd like to know if I'm doing them right. 1) What equation defines an exponential decay function? a) y=x^pi b) y=pi^-x c) y=(1/pi)^-x d) y=pi times x I think the answer is c. 2)...

18 years ago

Could you explain to me how to these type of problems? I checked in my book and it is still confusing. Evalute the piecewise function at the given value of the independent variable. 1. g(x)= {x^2+2 if x cannont equal 2, x+8 if x=2 Determine g(-5). 2. f(x)...

18 years ago

A freight train traveling with a velocity of -4.0 m/s begins backing into a train yard. If the train's average acceleration is -0.27 m/s/s, what is the train's velocity after 17 seconds? Can someone tell me which formula to use for this?

18 years ago

A bicyclist accelerates -0.87 m/s/s during a 3.8 s interval. What is the change in velocity of the bicyclist and the bicycle? For this problem, I used the formula 'change in v = a x t" and came up with -3.306 m/s as my answer. Is this right?

18 years ago

I have the equation 'change in distance = 1/2 x (vf+vi) x change in time (or delta t)' for uniform acceleration. However, I am totally lost when it comes to rearranging it. I need to rearrange it for inital speed (vi) and change in time (delta t). Can som...

18 years ago

A robot probe drops a camera off the rim of a 239 m high cliff on Mars, where the free-fall acceleration is -3.7 m/s^2. a) Find the velocity with which the camera hits the ground. b) Find the time required for it to hit the ground. Ok so I'm not even sure...

18 years ago

I'm learning about trigonometric functions, and my worksheet instructs me to find the "missing information" for each triangle. For the first one, they give me the length of the hypotenuse (45) and that theta = 35. How can I go about finding the missing in...

18 years ago

Again, I'm learning about trigonometric functions. I need to find the missing information for each triangle. I have the length of one leg as 24 and the opposite theta as 72. I need to figure out the other angles and side lengths, but I'm really not sure h...

18 years ago

A Cessna airplane can accelerate from rest to a ground speed of 78 knots in 29.8 s. What is the average acceleration of this airplane? I figured out that 78 knots is equal to 89.76 miles, 144.45 km, or 144,450 m. And I think the equation might be average=...

18 years ago

The airplane can take off when its airspeed (speed of the air flowing over the wing) is equal to 65 knots. What is the length of runway required for the plane to take off if there is a 22 knots head wind? The runway at the Tallahassee Regional Airport has...

18 years ago

-The brakes on your automobile are capable of creating acceleration of 19 ft/s2. If you are going 76 mi/hr and suddenly see a state trooper, what is the minimum time required to get your car to 55 mi/hr? For this answer, I got 1.62 s. -How far do you trav...

18 years ago

A golf ball released from a height of 1.80 m above a concrete floor, bounces back to a height of 1.06 m. If the ball is in contact with the floor for 4.62 ms, what is the magnitude of the average acceleration a of the ball while it is in contact with the...

18 years ago

What exactly is "cultural purity?" I think I understand the concept, but I'm having a hard time putting it into words.

18 years ago

A stone is thrown vertically upward. On its way up it passes point A with speed v, and point B, 12.6 m higher than A, with speed v/2. Calculate the maximum height reached by the stone above point B. What equation can I use to get the maximum height?

18 years ago

At the instant a traffic light turns green, a car starts moving with a constant acceleration a of 3.05 m/s^2. At the same time a truck, traveling with a constant speed of 10.15 m/s, overtakes and passes the car. How far beyond the traffic light will the c...

18 years ago

It takes 2.5 s for a small ball released from rest from a tall building to reach the ground. The mass of the ball is 0.05 kg. Calculate the height from which the ball is released. Ok so I have the time, initial velocity, and the acceleration. But the mass...

18 years ago

A basketball player, standing near the basket to grab a rebound, jumps 73.6 cm vertically. How much time does the player spend in the top 15.4 cm of his jump? I never know which formula to use for these problems! Any help will be greatly appreciated.

18 years ago

A basketball player, standing near the basket to grab a rebound, jumps 73.6 cm vertically. How much time does the player spend in the bottom 15.4 cm of the jump? I think I have this right, but I'd like someone to make sure. First I have to find the total...

18 years ago

A basketball player, standing near the basket to grab a rebound, jumps 73.6 cm vertically. How much time does the player spend in the bottom 15.4 cm of the jump? I've been told that I need to use the height of the jump to solve for V. Then I need to use t...

18 years ago

A basketball player, standing near the basket to grab a rebound, jumps 73.6 cm vertically. How much time does the player spend in the bottom 15.4 cm of the jump? Ok...after this I swear I'm done! I just need someone to check my final answer, which is 0.08...

18 years ago

I am given a velocity versus time graph for a runner. For it, I had to figure out the average velocity for the entire 16 s interval (for this, I got 2 m/s). Now they want me to find the displacement of the runner in the first 15.4 s. I know that it must b...

18 years ago

A rescue plane has to drop supplies to a group of castaways who are stranded on a deserted island. The plane is flying as 150 m/s at a level altitude of 1200 m. How far ahead of the landing zone should the plane release the supplies? I'm not even sure how...

18 years ago

Salmon, swimming up the Fraser river to their spawning grounds, leap over all sorts of obstacles. The unofficial salmon-altitude record is an amazing 3.58 m jump. Assuming the fish took off at 45.0°, what was its speed on emerging from the water? Ignore f...

18 years ago

A snowball is launched horizontally from the top of a building at v = 15 m/s. If it lands d = 44.5 meters from the bottom, how high (in m) was the building? For this problem, do I need to solve for any other velocities? I'm a little stuck...I'm not quite...

18 years ago

A stone thrown horizontally from a height of 7.8 m hits the ground at a distance of 12.0 m. Calculate the speed of the ball as it hits the ground. I was able to find the initial speed of the ball, which is 9.52 m/s. However, I'm unsure about whether I nee...

17 years ago

A small steel ball bearing with a mass of 24 g is on a short compressed spring. When aimed vertically and suddenly released, the spring sends the bearing to a height of 1.23 m. Calculate the horizontal distance the ball will travel if the same spring is a...

17 years ago

A ball is thrown horizontally from a height of 16.01 m and hits the ground with a speed that is 5.0 times its initial speed. What was the initial speed? This question really boggles my brain. I have no idea how to solve this, given only the height. Could...

17 years ago

A ball is thrown horizontally from a height of 16.01 m and hits the ground with a speed that is 5.0 times its initial speed. What was the initial speed? Ok so I got a vertical final velocity of 17.714 m/s. Now I need to find the horizontal speed, correct?...

17 years ago

A helicopter is flying in a straight line over a level field at a constant speed of 21.7 m/s and at a constant altitude of 11.5 m. A package is ejected horizontally from the helicopter with an initial speed of 21.6 m/s relative to the helicopter, and a di...

17 years ago

A stone is aimed at a cliff of height h with an initial speed of 62 m/s directed 45° above the horizontal, as shown in the Figure below. The stone strikes at A, 6.56 s after launching. What is the height of the cliff? Can someone please tell me which equa...

17 years ago

A catapult on a cliff launches a large round rock towards a ship on the ocean below. The rock leaves the catapult from a height H = 35.0 m above sea level, directed at an angle theta = 46.7° above the horizontal, and with a speed v = 28.4 m/s. Assuming th...

17 years ago

The soccer goal is 23.05 m in front of a soccer player. She kicks the ball giving it a speed of 17.97 m/s at an angle of 25.83 degrees from the horizontal. If the goalie is standing exactly in front of the net, find the speed of the ball just as it reache...

17 years ago

The launching speed of a certain projectile is 6.4 times the speed it has at its maximum height. Calculate the elevation angle at launching. I have noo idea how to start this one. Please help!

17 years ago

A regulation volleyball court is L = 18.0 m long and a regulation volleyball net is d = 2.43 m high. A volleyball player strikes the ball a height h = 1.76 m directly above the back line, and the ball's initial velocity makes an angle q = 55° with respect...

17 years ago

A cannon is fired from a cliff 190 m high downward at an angle of 38o with respect to the horizontal. If the muzzle velocity is 41 m/s, what is its speed (in m/s) when it hits the ground? Which equations do I need for this?

17 years ago

A cannon is fired from a cliff 190 m high downward at an angle of 38o with respect to the horizontal. If the muzzle velocity is 41 m/s, what is its speed (in m/s) when it hits the ground? I keep getting 64.28 m/s as my answer, but it's not right. Could so...

17 years ago

A cannon is fired from a cliff 190 m high downward at an angle of 38o with respect to the horizontal. If the muzzle velocity is 41 m/s, what is its speed (in m/s) when it hits the ground? Please check my work. I think it’s wrong, but I don’t know where I’...

17 years ago

We're studying projectile motion in my Physics class right now, and last week we went outside and hit tennis balls with a bat. Now we must make graphs showing the position of the ball in both the x and y directions. I must also explain why each line has t...

17 years ago

9b^2-(-4b)^2 is this 9b^2+4b^2 or 9b^2+16b^2?

17 years ago

A block of mass 7.5 kg is pulled along a horizontal frictionless floor by a cord that exerts a force of 31.0 N at an angle 26.3° above the horizontal. What is the magnitude of the acceleration of the block? I have nooo clue what to do for this one. Can so...

17 years ago

A car that weighs 14900.0 N is initially moving at a speed of 57.0 km/hr when the brakes are applied and the car is brought to a stop in 4.8 s. Find the magnitude of the force that stops the car, assuming it is constant. I found a using Vf=vi+at...a = 11....

17 years ago

A man stands on a scale in an elevator that is accelerating upward. The scale reads 731.6 N. When he picks up a 35.0 kg box, the scale reads 1108.2 N. The man weighs 68 kg. What is the acceleration of the elevator? What do I need to do in order to solve t...

17 years ago

A research balloon of total mass 200 kg is descending vertically with a downward acceleration of 3.2 m/s^2. How much ballast must be thrown from the car to give the balloon an upward acceleration equal to 2.8 m/s^2, presuming that the upward lift of the b...

17 years ago

A railroad flatcar is loaded with crates. The coefficient of static friction between the crates and the floor is 0.27. If the train is moving at 59.7 km/hr, in how short a distance can the train be stopped with a constant acceleration without causing the...

17 years ago

A 5.70 kg block located on a horizontal floor is pulled by a cord that exerts a force F = 10.4 N at an angle theta = 27.5° above the horizontal. The coefficient of kinetic friction between the block and the floor is 0.10. What is the speed of the block 6....

17 years ago

A 850.0-kg car travelling on a level road at 27.0 m/s (60.5 mi/hr) can stop, locking its wheels, in a distance of 61.0 m (200.1 ft). (a) Find the size of the horizontal force which the car applies on the road while stopping. (b) Find the stopping distance...

17 years ago

A hockey puck is sliding across a frozen pond with an initial speed of 6.5 m/s. It comes to rest after sliding a distance of 7.6 m. What is the coefficient of kinetic friction between the puck and the ice? I know this one is not that difficult. However, I...

17 years ago

A block of mass M1 = 160.0 kg sits on an inclined plane and is connected to a bucket with a massless string over a massless and frictionless pulley. The coefficient of static friction between the block and the plane is ms = 0.52, and the angle between the...

17 years ago

This is the info for the problem: A block of mass M1 = 160.0 kg sits on an inclined plane and is connected to a bucket with a massless string over a massless and frictionless pulley. The coefficient of static friction between the block and the plane is ms...

17 years ago

The Wall of Death in an amusement park is comprised of a vertical cylinder that can spin around the vertical axis. Riders stand against the wall of the spinning cylinder and the floor falls away leaving the riders held up by friction. The radius of the cy...

17 years ago

Three very small spheres are located along a straight line in space far away from everything else. The first one (with a mass of 2.43 kg) is at a point between the other two, 10.60 cm to the right of the second one (with a mass of 5.17 kg), and 20.70 cm t...

17 years ago

My last problem for the day: A) The centers of two 11.00 kg spheres are separated by 0.09 m. What is their gravitational attraction? I got 9.96 x 10^-7 N. B) What is the ratio of this attraction to the weight of one of the spheres (at the surface of the E...

17 years ago

Consider a spaceship located on the Earth-Moon center line (i.e. a line that intersects the centers of both bodies) such that, at that point, the tugs on the spaceship from each celestial body exactly cancel, leaving the craft literally weightless. Take t...

17 years ago

Suppose that the ratio of the Moon's mass to the Earth's mass is given by 1.200E-2 and that the ratio of the Moon's radius to the Earth's radius is given by 2.700E-1. Calculate the ratio of an astronaut's Moon-weight to Earth-weight. Now it seems like thi...

17 years ago

Two 2.160 kg crystal balls are 0.870 m apart in the vertical direction. Calculate the magnitude of the gravitational force they exert on a 8.80 g marble located 0.260 m horizontally out from the center of a line that intersects the centers of the balls. (...

17 years ago

I still cannot solve this problem: Consider a spaceship located on the Earth-Moon center line (i.e. a line that intersects the centers of both bodies) such that, at that point, the tugs on the spaceship from each celestial body exactly cancel, leaving the...

17 years ago

In a quadrilateral ABCD, Angle A = 120 degrees, Angle B = 140 degrees. The bisectors of the angles C and D meet at the point Y. What is the size of the angle DYC?

17 years ago

How much torque is applied to a bicycle wheel whose radius is 0.40 m in order to accelerate the 15 kg bike and 78 kg rider at a rate of 3.4 m/s^2? I'm totally lost on this one. Which equation do I need to use?

17 years ago

A 2.6 m long, 16 kg piece of plywood is sitting on a pair of sawhorses. The sawhorses are .3 m from the left end and .5 m in from the right end of the plywood. A 4 kg circular saw is sitting 1 m in from the left end of the plywood. How much force is each...

17 years ago

x=3y-4 2x-y=7 solve as a set/substitution.

17 years ago

A car traveling at a constant speed of 125 km/hr passes a trooper hidden behind a billboard. One second after the speeding car passes the billboard, the trooper sets in a chase after the car with a constant acceleration of 2.7 m/s^2. How far does the troo...

17 years ago

A flea pulls on a puck with force 7 microN at an angle of 30°. Another flea pulls on the puck with force 2 microN at an angle of -60°. a) What is the magnitude of the net force on the puck? (I got 7.28 uN) b)At what angle is the net force? ( I got about 1...

17 years ago

During World War 2, there were some cases where the crew fell out of burning aircraft without a parachute and survived the fall. Assume that the crew member reached a constant terminal speed of 128.3 km/hr prior to hitting a stack of loose hay. If the cre...

17 years ago

I had to do a learning project in Psych. For my project I taught myself to make my bed every day using operant conditioning. If I made my bed within 5 mintues of waking up, my mom would give me 5 dollars. I know this is positive reinforcement. However, I...

17 years ago

My class is making sailboats out of styrofoam. Basically we are given a block of styrofoam, some plastic bags/wooden dowels for the sails, and a little piece of metal for the keel that is either extremely light or a little heavier, whichever we want. When...

17 years ago

How do the mainsail and the jib of a sailboat help the boat sail? What do these two sails have to do with force?

17 years ago

rewrite using radicals and rational numbers Cos 3(pi)/8

17 years ago

If the density of a substance is 7.87 g/cubic cm, convert this density to g/cubic inches.

17 years ago

in y= mx+b m=rise/run what is b for?

17 years ago

4x+y=3 find the slope using the slope form formula y=mx+b slope=rise/run

17 years ago

what does multiplying a complex number by a real number do to its polar representation?

17 years ago

in chapter 6 what is 1)contrast the attitudes of jack and ralph to the news of the beast. 2)what us the beast from the air? and 3) what is meant by "Piggy hung about near for all his brave words?"

17 years ago

If you lived on Mars, which planets would describe retrograde loops? Which would never be visible as crecent phases?

17 years ago

If a space probe were sent into orbit around the sun that brought it as close as 0.5 AU to the sun and as far away as 5.5 AU, what would its orbital period be? Can I use Kepler's 3rd law for this? I'm not sure how to take into account both AUs...

17 years ago

A steam engine's boiler completely converts 155 kg of water to steam. This process involves the transfer of 3.5 x 10^8 J by heat. If steam escaping a safety valve does 1.76 x 10^8 J of work against the outside atmosphere, what is the net internal energy o...

17 years ago

The burning of gas in a car produces about 12,600 kJ/gallon of energy. If a car averages 35 km/gal when driving 90 km/hr, which requires 18.5 kW, what is the efficiency of the engine under those conditions? ...please help?

17 years ago

A lead ball, with an initial temperature of 25.0oC, is released from a height of 96.0 m. It does not bounce when it hits a hard surface. Assume all the energy of the fall goes into heating the lead. Find the temperature (in degrees C) of the ball after it...

17 years ago

When you release the arm of a trebuchet and the projectile is released, I know that energy is lost/wasted. Can someone give me some good examples of what happens to this energy?

17 years ago

My question had 2 parts: a) A 2.0 kg object oscillates with simple harmonic motion on a spring of force constant 580.0 N/m. The maximum speed is 1.0 m/s. What is the total energy of the object and the spring? Answer: 1.0 J b) What is the maximum amplitude...

17 years ago

What is the smallest a flat mirror can be while still being able to see your full reflection? I need to show my work/explain. Can anyone help me?

17 years ago

-An object whose height is 5.8 cm is at a distance of 9.5 cm from a spherical concave mirror. Its image is real and has a height of 9.2 cm. Calculate the radius of curvature of the mirror. I got 0.1165 m for my answer. -How far from the mirror is it neces...

17 years ago

Choose the true statements regarding the charge-minimized Lewis structure(s) of the BrO2- ion. (selet all that apply) a. There is only one charge-minimized structure for this ion. b. There are two charge-minimized resonance structures for this ion. c. The...

17 years ago

Im's So confused about stoichiometry. My question is this use stoichiometric calculations to predict the mass of solid product fromed in the reaction from the knwon mass of sodium hydrogen carbonate used. Balenced equation: 4NaHCO3 = 4Na + 2H2O + 4CO + 3O...

17 years ago

Where can I find information on decarboxylases, kinases, etc and their function? I look everywhere, but the only information I can find is on wikipedia...

16 years ago

what is the difference between a predicate and a verb? is a predicate a type of verb and if it is then how can i tell when it is just a verb and when it is a predicate

16 years ago

Can someone explain to me why the intersection of two infinite sets is not always an infinite set, but the union of two infinite sets is?

16 years ago

considering the polarity of each compound and that of a solvent in which it is dissolved (including the potential for hydrogen bonding), give a brief explanation of each result: a) malonic acid in water - which i know is soluble b) malonic acid in hexane...

16 years ago

What is the main verb in this sentence...This dog food is made for larger dogs?

16 years ago

If the freezing point depression (DTf) is 5.62 and the freezing point depression constant (Kf) is 3.90, what is the molality of the solution? Assume that the solute is a nonelectrolyte (i = 1).

16 years ago

An unknown solute (a nonelectrolyte) was obtained and 5.37 g was weighed out. After dissolving the solute in water, the mass of the solution was 26.58 g. From the experimental results, the freezing point depression was found to be 3.6oC. If the freezing p...

16 years ago

What is the process that occurs when solvent molecules surround a solute?

16 years ago

When dissolved in water, ammonium phosphate would have a value of __________ for i solute.

16 years ago

Sound enters the ear, travels through the auditory canal, and reaches the eardrum. The auditory canal is approximately a tube open at only one end. The other end is closed by the eardrum. A typical length for the auditory canal in an adult is about 2.6 cm...

15 years ago

The first row of a concert hall has 25 seats and each row after the first has one more seat than the row before it. There are 2 rows of seat. 1)Write a rule for the number of seats in the nth row. 2)35 students from a class want to sit in the same row. Ho...

15 years ago

A vet surveys 26 of his patrons. He discovers that 14 have dogs. 10 have cats. 5 have fish. 4 have dogs & cats. 3 have dogs & fish. 1 has a cat & a fish. Use a diagram to answer the following question: If no one has all 3 kinds of pets, how many patrons h...

15 years ago

Answers

The following answers were posted by visitors named Lindsay.

So for part A, I got 6.38 hours because I added 3.18, 2.8 (210 km/75) and .40 together. Is this correct?

18 years ago

Ok good. Then, for part B...I got 76.8 for the average velocity. ...I sure hope this is correct...!

18 years ago

Thanks. :)

18 years ago

In order to get the time, would I have to do the vf-vi divided by 2, times the distance?? I guess I really do need a brush-up on algebra!

18 years ago

**Oops, I meant vf+vi. Is that the right equation?

18 years ago

Ok so I plugged in the numbers and got 42.1 for a) and -11.4 for b). However, my book says that I got them switched...that 11.4 s is a) and -42.1 m/s is b). How did this happen?

18 years ago

Ok cool, I got that. Thanks a lot. However, this next one gives me the length of one leg (359) and the adjacent theta of 83. How exactly can I solve this?

18 years ago

I try this and I get 2.62 knots/s^2, but it says this answer is wrong. Is it?

18 years ago

N/m, I needed to convert to knots to meters per second. I got the right answer. Thanks for the help, Quidditch. :)

18 years ago

43 knots, right?

18 years ago

I'm sorry. There was a problem before it where I had to figure out the average acceleration, and that was 1.35 m/s^2. Which fomula can I use to get the length of the runway?

18 years ago

To get how many seconds, would I have to take the 43 knots and divide it by 1.5?

18 years ago

43 knots is 22.097 m/s. So could I now do 22.097 divided by 1.35?

18 years ago

Ok, so I came up with 16.37 s as my answer for the time. So I do I simply plug that number into the equation 'distance=1/2 x a x t^2' and that is my runway length?

18 years ago

THANKS! :)

18 years ago

**Oops sorry, my sister was using this site last night for Chemistry.

18 years ago

Ok great, I get it now. Thanks!

18 years ago

What information must I use to get the velocities?

18 years ago

THANK YOU!

18 years ago

So, am I supposed to figure out v2? And what is g, in this case?

18 years ago

Now, when I'm solving for time, do I not yet know what v/2 is? Like, it would just be "t = v/2 x -9.8?" I'm so sorry...this is just not making any sense to me yet.

18 years ago

What exactly do you mean by "set them equal?"

18 years ago

Ok, the time I got was 2.624 s. Now what?

18 years ago

Which equation am I using for distance?

18 years ago

Right. I plug in "1/2 x 3.05 x (2.58^2") and come out with 10.15 m. But that's obviously not correct. I know I'm doing something wrong, but I'm just not sure what. I'm sorry...this just isn't making much sense yet.

18 years ago

Ohhh ok I see my mistake! Thanks for your patience. :)

18 years ago

Never mind! The mass has nothing do with the problem. I got it. :)

18 years ago

To find the time, would I have to use the formula "x = vt + 1/2at^2?"

18 years ago

I found the time. Now I just have to double it, and that will be the time he spent in the top 15.4 cm?

18 years ago

Ok n/m, I got the answer. However, now it asks for the time in the bottom 15.4 cm. Do I have to use my time from the first problem to figure it out?

18 years ago

When finding the times, do I have to switch the cm to m?

18 years ago

How can I solve for V if I don't yet have the time?

18 years ago

But don't I need time in order to find the initial velocity?

18 years ago

See, I use your method without rounding and now come up with 0.0852 s. So...now I'm a little stuck on which answer is the correct one.

18 years ago

Great I got it, thanks. :)

18 years ago

Thanks, I got it now. :)

18 years ago

THANK YOU!

18 years ago

15.6 m/s. I understand now, thanks a bunch.

17 years ago

Once I then have the initial vel., how can I go about getting the horizintal distance? Don't I need time?

17 years ago

Ahh ok I got it now. Thanks. :)

17 years ago

Ok makes sense. The only part I'm a little confused about is finding the horizontal speed...which equation is that?

17 years ago

But my number was correct, right? 17.714 m/s?

17 years ago

And drwls...where is 0.2041 coming from?

17 years ago

All right. So this is what my equation looks like so far. I need to solve for Vx: 25Vx^2 = 313.786 + Vx^2 Correct?

17 years ago

All right n/m, I finally got the answer. :)

17 years ago

Thanks!

17 years ago

How did you come up with 39.96 Vh^2?

17 years ago

This is probably really obvious, but I'm still not undertanding why you have to subtract one.

17 years ago

Now it asks for the max. height. above the court reached by the ball. Do I use the equation Vf^2 = vi^2 + 2(g)(delta y) ?

17 years ago

Ok so I have the initial speed and the max height. Now it asks "At what initial speed must the ball be hit so that it lands directly on the opponent's back line?" Do I use a process similar to that of the first question?

17 years ago

Would my equation for the x-dir. be Vcos 55*T = 18, since it's the full length of the court? What would my height for the y-dir. be? Vsin 55*T - (g/2)T^2 = ???

17 years ago

V is 41 m/s, right?

17 years ago

I keep getting 64.28 m/s as my answer, but it's not right. What am I doing wrong?

17 years ago

Would 59.5 be the final answer?? B/c that is not right, either...

17 years ago

I keep getting the same answer as you. This is what I did to get my original answer: V^2 = sqrt[Vx^2 + Vy^2] where... Vx = 41 m/s * cos 38 Vy at impact can be calculated using Vy^2 = (41 sin 38)^2 + 2 g H I got 55.56 as my Vy. I have a feeling this is whe...

17 years ago

You might have to correct me if I'm wrong, but I think... In order to calculate overtime pay, you must take your amount earned per hour and multiply it by 1.5. In your case, Eric's overtime rate would be $13.86/hour ($9.24 x 1.5 = $13.86). For double time...

17 years ago

There really is no formula for this. All you must do is add 8 to both sides. What you do to one side, you must do to the other. w-8 = 9 w-8(+8) = 9(+8) The eights cancel out on this side. Now you are simply left with w = 17. Make sense?

17 years ago

Hmm yeah I figured Vfy was wrong. But I'm still a little confused on which I equation I DO need to use.

17 years ago

I finally got the right answer. And I was using the right equation for Vfy, just not using the right numbers.

17 years ago

16.73 is the final?? Because again, it's not right. Hmm...

17 years ago

Ahh ok I see. There isn't anything I should add to them? I just want to make sure they are as complete as possible.

17 years ago

Great, thanks. That helps a lot. But now I have to do a graph of velocity and the x/y directions. My velocity in the x-direction is a staight line, and the vel. of the y continually decreases. They ask me to explain why each line has the shape that it doe...

17 years ago

I come up with 13.6 N as my net force. Is this correct?

17 years ago

17? I come up with 19, but you might want to double check that.

17 years ago

C2H6 = 14 valence electrons There are 4 valence electrons in a C, so in 2 C there is 8. H has only one. 8 + (1 x 6) = 14 v.e.

17 years ago

Now it asks for the normal force exerted on the mass by the floor. Do I need to use the acceleration for that?

17 years ago

m is 68 kg?

17 years ago

I come up with 0.96 m/s^2. Is this correct?

17 years ago

N/m I finally got it. Thanks for all your help. :)

17 years ago

For lift I got 1320, and for deltamass I got 304.76. Is this right? If so, do I have to add those to the netforce?

17 years ago

How do I find the mass?

17 years ago

See, I thought that was right, too. But I plug that into my computer and it says it's not right. So I'm not sure what I'm doing wrong...

17 years ago

I come up with 0.233 m as my answer, but that's not right. What am I doing wrong?

17 years ago

So wait...do I use cos 15 to find the acceleration?

17 years ago

Ohh ok great I understand. Thanks a lot. :)

17 years ago

I came up with 5079 N as my answer to a. Is that correct?

17 years ago

Yeppp n/m it is correct. Thanks a lot. :)

17 years ago

Ahh ok, I didn't realize the masses cancel out. But of course you're right. That really was easy. :)

17 years ago

What is V, in this case?

17 years ago

A youngster shoots a bottle cap up a 15.0° inclined board at 1.92 m/s. The cap slides in a straight line, slowing to 0.95 m/s after traveling some distance. If the coefficient of kinetic friction is 0.35, find that distance. So I get that (1/2)MV^2 = MgX*...

17 years ago

I keep getting 0.315 m, but that's not right. What am I doing wrong?

17 years ago

I've entered this into the computer, but it says it's not right. Hmmmm...

17 years ago

Ok I understand that part. Now it asks for the minimum magnitude of F that will start the block moving up the plane, and the magnitude of F that is required to move the block up the plane at constant velocity. Is it a similar process for both?

17 years ago

49% is 0.49 as a decimal, and 80% is 0.80 as a decimal. 0.49 x 0.80 = 0.392, or 39.2%

17 years ago

Do you come up with an answer of 33.91? Because that's what I get.

17 years ago

Why is it sin and cos of 23.5? I thought the angle was 21.6...

17 years ago

Using 21.6 as the angle for both cos and sin, I come up with 33.91, which is the incorrect answer. Am I still doing something wrong?

17 years ago

That's right. Now it asks for the minimum value of M2 for which the system will remain at rest. Do I still use mgSinTheta-mg*mu*CosTheta?

17 years ago

Ok I got it, thanks. The last part is this: Suppose the coefficient of kinetic friction between the block and the inclined plane is muk = 0.36. If M2 = 217.1 kg, what is the magnitude of the acceleration of M1? Which equation am I using for this?

17 years ago

Ahhh ok that was what was wrong. Thanks a ton. :)

17 years ago

I tried both of the ways and got the same answer. However, the answer I got using bobpursley's equation got me -5.11E-8, when it was really positive. Was there an error in that equation, or did I just mess up with the math somewhere along the way?

17 years ago

Great I got it, thanks for all your help.

17 years ago

Oh wait...do I need to use F = GM1M2/d^2?

17 years ago

Ok I understand that. But what is the distance from craft to earth?

17 years ago

Oh ok I see. Well, my online homework site would only accept it as postive, but it has been known to make errors before.

17 years ago

Actually, that just made me even more confused. I still don't know what I'm supposed to use as the distance from the spaceship to the earth. Thanks, tho.

17 years ago

Right. But w/o knowing the actual mass of the earth and moon, only the ratio, how can I do this?

17 years ago

Ohhh I see now! Sorry, I just wasn't understanding before. Thanks. :)

17 years ago

(6.67E-11)(2.16)(0.0088) / (0.5068)^2 = 4.94E-12 N Is that correct?

17 years ago