tyger2020

A 7.77 kg pumpkin falls from a height of 12.3m. It hits the ground and comes to an abrupt stop in about 444 ms. What is the average force imparted by the ground (aka 'Normal Force') on the pumpkin?

8 years ago

A baseball and a ball of clay are approaching each other. The mass of the baseball is 145 g and it is moving due west 5 m/s at 180 degrees. The ball of clay is 290 g and it is moving northwest at 135 degrees at 4 m/s. What is the magnitude of their combin...

8 years ago

While punting a football, a kicker rotates his leg about the hip joint. The moment of inertia of the leg is 3.75 kg/m2 and its rotational kinetic energy is 175 J. What is the angular velocity of the leg, in rad/s ? I'm not even sure where to start...

7 years ago

What is the angular momentum of the Moon in its orbit around Earth in kg m2/s? I do not have any information about the moon, so I looked it up, but I got the question wrong so I don't know what values I should be using...I got 5.7 * 10^35. Thank you!

7 years ago

Consider a system like the example problem where a batting machine swings a bat but instead of a baseball, the bat hits a lump of clay, which sticks to the end of the bat. How does the angular momentum of the clay and bat after the collision compare to th...

7 years ago

Suppose you start an antique car by exerting a force of 300 N on its crank for 0.250s. What angular momentum is given to the engine if the handle of the crank is 0.300 m from the pivot and the force is exerted to create maximum torque the entire time?

7 years ago

A 33kg child named Lindsey runs as fast as she can and jumps onto the outer edge of a merry-go-round. The merry-go-round is initially at rest and has a mass of 78kg and a radius of 2.20m. Lindsey's linear velocity was 9 m/s at the moment she jumped onto t...

7 years ago

What is the angular momentum of the Moon in its orbit around Earth? I assume I need the mass of the moon, radius of the moon, and angular velocity of the moon. Found those on google, plugged them into my formula (Iw) and got the wrong answer...

7 years ago

What is the angular momentum of the Moon in its orbit around Earth? I assume I need the mass of the moon, radius of the moon, and angular velocity of the moon. Found those on google, plugged them into my formula (angular momentum = Iw) and got the wrong a...

7 years ago

If a 2000kg coaster is moving at 10 m/s on the top of the loop, what is the magnitude of the normal force that the track applies to the coaster? Normal force = mg cos theta But if theta is 90 degrees, in this case (I'm assuming, because the coaster is per...

7 years ago

Assume an aluminum platter that is 3.5 inches in diameter, 1mm thick, and spinning at 5400 rpm. Treat the platter as a solid disk. What is its angular momentum in kg-m/s? angular momentum = Iw. However, moment of inertia requires mass, and I am not given...

7 years ago

A 7kg mass on a 12 N/m spring oscillates with an amplitude of 23cm. What is the frequency of its oscillation in Hz? Find the period - 2pi * sqrt(m/k) = 4.799 frequency = 1 / period = 0.208 Is that right?

7 years ago

Which has a greater resistivity? 1. A copper rod that is shaped like a rectangular prism with dimensions of 1cm x 1cm x 1000m 2. A copper rod that is shaped like a solid cylinder with diameter 1cm and length 1000m I think it should be the rectangular pris...

7 years ago

Two identical waves undergo pure constructive interference. How is the resultant intensity related to that of the individual waves? A. resultant intensity is half of wave intensity B. resultant intensity is same as individual wave intensity C. resultant i...

7 years ago

To increase intensity of a wave by a factor of 50, by what factor should the amplitude be increased? This is also coming from the homework based on topics the video didn't cover. I know that power is proportional to amplitude squared, but what does this h...

7 years ago

What factors affect the frequency of a wave? A. the amplitude B. the energy of the wave C. the wavelength of the wave D. the material through which it travels E. the velocity of the wave I said C,D, and E. Should there be anything else?

7 years ago

In order to wake a sleeping child, the volume on an alarm clock is tripled. Under this new scenario, how much more energy will be striking the child's ear drums each second? A. twice as much B. three times as much C. approximately 4.8 times as much D. six...

7 years ago

Which harmonic frequencies can be detected in a tube closed at one end whose fundamental frequency is 200 Hz? 200 Hz 300 Hz 400 hz 600 Hz 1000 Hz It's a select multiple and I said the last three which was wrong.

7 years ago

Two balls have 3 nC of excess charge and are 10cm apart. What is the magnitude of the repulsive force on each? Electric field = 27,000 Charge = 3e-8 Coulombs F = EQ = 8.1e-4 ...which is wrong.

7 years ago

A trombone player stands at the end zone (x = 0) of a football field and begins to play its fundamental tone. Assume the trombone is a half open tube that is 3m long. How much would the trombone player have to move the slider in cm to play 25 Hz? I calcul...

7 years ago

In the methane molecule, CH4, each hydrogen atom is at a corner of a regular tetrahedron with the carbon atom at the center. In coordinates for which one of the C-H bonds is in the direction of i + j + k, an adjacent C-H bond is in the i - j - k direction...

7 years ago

A jet plane is flying at a constant altitude. At time t1 = 0, it has components of velocity vx = 88 m/s, vy = 115 m/s. At time t2 = 30s, the components are vx = -175 m/s, vy = 35 m/s. a) Sketch the velocity vectors at t1 and t2. (figured that out on paper...

7 years ago

A man stands on the roof of a 15.4 m tall building and throws a rock with a speed of 29.0 m/s at an angle of 33.3 degrees above the horizontal. Calculate A) the maximum height above the roof that the rock reaches B) the speed of the rock just before it st...

7 years ago

A force of 75 N is applied to two boxes stacked on top of each other. The coefficient of kinetic friction between the bottom box and the floor is 0.3. If the box on top is to accelerate at the same rate as the box on the bottom, what must the minimum coef...

7 years ago

A force described by F(t) = ½ t2 – 5t acts on an object from t = 0 to t = 3 seconds. The object, which has a mass of 2 kg, is at rest at t = 0. Determine the velocity of the object at t = 3 seconds.

6 years ago

Serious bicyclists say that if you reduce the weight of a bike, it is more effective if you do so in the wheels rather than in the frame. Why would reducing weight in the wheels make it easier on the bicyclist than reducing the same amount in the frame?

6 years ago

When an acrobat walks on a tightrope, she extends her arms straight out from the sides. She does this to make it easier for her to catch herself if she should tip from one side to the other. Explain how this works. Maybe something with center of mass? Thi...

6 years ago

Why must a water skier moving with constant velocity lean backward? What determines how far back she must lean?

6 years ago

A 3m long, 290N uniform rod is held in a horizontal position by two ropes at its ends. The left rope makes an angle of 150 degrees with the rod, and the right rope makes an angle theta with the horizontal. An 86 N howler monkey hangs motionless 0.5 m from...

6 years ago

I posted this before and didn't get an answer but I'm still stuck... A 3m long, 290N uniform rod is held in a horizontal position by two ropes at its ends. The left rope makes an angle of 150 degrees with the rod, and the right rope makes an angle theta w...

6 years ago

A satellite moves in a circular orbit of radius 35.793 km. The Earth's radius and mass are Re = 6.37e6 m, and Me = 5.97e24 kg. For the satellite, calculate the work done to put the satellite in orbit (mass of satellite is 1000 kg).

6 years ago

Why do we not see a lunar eclipse during each full moon when the earth is in between the Sun and the Moon? Does it depend on the seasons? I looked this up online, and it seems like there is always a lunar eclipse when the earth is between the Sun and Moon...

6 years ago

A compound metal bar has 4 kg of copper making up the first third of the bar, while the remainder is made of 12 kg of lead. The bar is 3 meters in length. In addition, a mass of 2 kg is hung 1m from the left end of the bar, and a mass of 6 kg is hung 2m f...

6 years ago

A container filled with 20 identical marbles spills over and all the marbles fall towards the ground in a random pattern. What is the acceleration of the center of mass of the group of marbles as they fall? Shouldn't that just be acceleration due to gravi...

6 years ago

A painter is on a scaffold that hangs by two ropes. The scaffold weighs 2500 N, and the painter weighs 800 N. The breaking point of each rope is 2100 N. _____|____________________|_______ 0m 1m 5m. 6m This diagram shows where each rope is placed. a. If th...

6 years ago

A yo-yo with mass M and radius R is wound with a light string. Someone drops it from rest with the string attached to a metal pole. The yo-yo falls and unwinds (spins) without slipping. The moment of inertia for the yo-yo is ½ MR^2 (a disk). a. In terms o...

6 years ago

A gunman standing on a sloping ground fires up the slope. The initial speed of the bullet is v0= 360 m/s. The slope has an angle α= 28° from the horizontal, and the gun points at an angle θ from the horizontal. The gravitational acceleration is g=10 m/s2....

6 years ago

A small cube of mass m1= 1.0 kg slides down a circular and frictionless track of radius R= 0.5 m cut into a large block of mass m2= 4.0 kg. The large block rests on a horizontal and frictionless table. The cube and the block are initially at rest, and the...

6 years ago

A uniform rod of mass M and length d is initially at rest on a horizontal and frictionless table contained in the xy plane, the plane of the screen. The rod is free to rotate about an axis perpendicular to the plane and passing through the pivot point at...

6 years ago

I'm reposting this one because I'm still stuck... A uniform rod of mass M and length d is initially at rest on a horizontal and frictionless table contained in the xy plane, the plane of the screen. The rod is free to rotate about an axis perpendicular to...

6 years ago

Construct a frequency distribution with five classes for the following data: 82, 76, 88, 77, 90, 71, 66, 120, 111, 108, 93, 116, 74. There are 13 data points, so how do I divide them into five classes of equal size?

6 years ago

WAIT! I got it now...made a mistake.........

8 years ago

Edit: I now got 3.14 m/s as the answer, which is still wrong.

8 years ago

Thank you! @Scott Using this method though, I get 7.06 as an answer...where am I making an error? 7.06 isn't even an answer choice for this problem? My choices are 9, -0.255, 1.75, and 4.02

8 years ago

Thank you!!

7 years ago

The correct answer is B. the equation is: 4.5 + 0.75d (car 1) = 7.5 + 0.65d (car 2) which is choice B.

7 years ago

Did you figure it out? First we can simplify. If there are 1000 meters in 1 kilometer, how many meters are in 2 kilometers? How about in 3 kilometers? You're grouping quantities together - with smaller quantities, how many inches in 3 feet if one foot is...

7 years ago

I don't see choices, but 74% = .74 so, .74(44) = money kept How many days? Let's say d days. Money donated = 44d - .74(44d). You can substitute your number of days in this expression.

7 years ago

The answer is C. Kinetic energy = 1/2 mass * velocity squared. 27,000 = 30kg * 30m/s * 30 m/s.

7 years ago

@Steve thanks! I reposted the question with more details

7 years ago

p = 15 + r where p = pencils and r = rulers. b = 3r where b = books total number of items = p + b + r = 15 + r + 3r + r = 15 + 5r. p - 15 + 3(p-15) + p is how you express in terms of p. p - 15 + 3p - 45 + p = 5p - 60 is the total in terms of p.

7 years ago

Radius is 5m... Does that mean the answer would be 20,400?

7 years ago

Ok, still getting 20,400 because I know the car is upside-down in the loop.

7 years ago

That's right - thank you! :)

7 years ago

Is it 9.36 * 10^-3 (angular momentum)? That seems awfully small

7 years ago

Yep! It is! Thank you!

7 years ago

What about for resistivity though?

7 years ago

Aha! Thank you! I got them both right now!

7 years ago

You shouldn't be looking for straight-up answers... it would probably help you to know that the area of a triangle is 1/2 the base multiplied by the height. Then you can do the problems on your own.

7 years ago

Energy - the ability to do work or cause change

7 years ago

I still get 7.1e-4 with this equation

7 years ago

For the nonlinear equation, it can be something like: (x + 2) * (x - 5) and then FOIL it out like this: x^2 - 3x - 10 You can substitute any two different integers for 2 and -5 there, and it will be a nonlinear function with two solutions. For a linear eq...

6 years ago

I'd say B It certainly led to the start of the American revolution, but it officially started with the Battle of Lexington.

6 years ago

Diagram got weird -- the second rope is supposed to be at position 5m, near the end of the scaffold.

6 years ago

I just figured it out :)

6 years ago

Yes, A looks right

6 years ago