Quidditch

Calculate the total cost of each game including tax--remember that 8.125% = 0.08125 total cost = game + tax = $3.95 + 0.08125($3.95) Now divide the money he has ($20.92) by the total cost per game. Disregard any remainder/fraction/decimal of a game since...

17 years ago

You probably mean: =0, not +0 Factoring, (a+12) (a-6)=0 two values for a will give 0 so...?

18 years ago

Take a guess that the answer is a line. Use any to points where the term number is x and the term value is y. Sove for the slope and intercept. Terms 2 and 4 would give: m * 2 + b = 10 m * 4 + b = 18 m = (18 - 10) / (4 - 2) = 8 / 2 = 4 If m = 4, what is b...

18 years ago

The 100th term will be: 100 * m + b m = 4 and b = ? The 100th term is 402

18 years ago

Recall that a prime number can not be divided evenly by any number except itself and 1. The first several primes are 2, 3, and 5. try 2 180/2 = 90 180/2 = 45 45 is not evenly divisible by 2. try 3 45/3 = 15 15/3 = 5 5 is a prime. So now the prime factoriz...

18 years ago

Separate y into x pieces. y/x would represent this.

18 years ago

for the expression y =2 ^ (-t/4), the inverse function is the function which t = f(y). If we solve the above function for t in terms of y: taking the log of both sides log(y) = log(2 ^ (-t/4)) log(y) = (-t/4)*log(2) (log(y))/(log(2))=-t/4 -4*(log(y))/(log...

18 years ago

Look for ways to express given values. If there are two things you are trying to find out, try to express one of them in terms of the other. Solve the equation of one variable, then use the relationship to find the other variable. Let x = number in back o...

18 years ago

If you have the three points of a triangle, could you draw one line through them all?

18 years ago

Correct, so A is false.

18 years ago

Use the second equation to express one variable in terms of the other variable. Substitute that into the first expression. Expand and combine the terms. Solve by inspection of the quadratic forumula.

18 years ago

Oops! I meant to say: Solve by inspection OR the quadratic forumla.

18 years ago

Here, no quadratics required, luckily. solving the second equation for y in terms of x y = (3/4) * x substituting into the first equation x^2 + y^2 = 25 yields x^2 + ( (3/4) * x)^2 = 25 x^2 + (9/16)*(x^2)=25 combining terms (25/16) * (x^2)= 25 x^2 = 25 *...

18 years ago

exactly the same multiply the the coeffecient by exponent and subtract one from the exponent. -200 P ^-3

18 years ago

Check your work above. There is an error in the value on the left side. Fix that before the next step.

18 years ago

Go back and look at what you wrote. You are on the right path. You already know the value of d. It is 6m. You should not have put the value in for a, the acceleration. That is what you are trying to find. 6m = (1/2) * (a)* (1.9s)^2 Solve for a

18 years ago

You are thinking correctly. Delta v over delta t expresses acceleration. delta v = 78kts (nautical miles/second) (convert to other units if desired. delta t = 29.8s average acceleration = (78/29.8) nautical miles/sec^2.

18 years ago

starting hint: 2 + what = 3?

18 years ago

Recall force = mass * acceleration

18 years ago

Objects can have an acceleration, but not be moving. When you are standing still, you are still experiencing the acceleration of gravity. C is not correct

18 years ago

Remember to add or subtract terms to get all terms on one side of the equals and zero in the other side. Then, plug the coeffecients into the quadratic equation.

18 years ago

Sometimes it helps to get rid of those pesky fractions. Try multiplying both sides by 12 and then working the problem. If you multiply everything on both sides of an equals by the same value it will not change the value of the variable you are trying to f...

18 years ago

There are times where they do not factor nicely. A quick check is to calculate the sqrt(b^2 - (4*a*c)) part of the quadratic equation. Here it looks like that would be sqrt(28) or 2*sqrt(7). This pretty much says it is not easily factored by inspection. U...

18 years ago

the formula that helps is: distance = v * t + (1/2)(a *t^2). Where a=acceleration, v=initial velocity, and t=time. Be very mindful of the sign for acceleration.

18 years ago

It might help to sketch a picture. The rope is at an angle of 36 degrees. It is usually important to know the x and y (horizontal and vertical) vectors from the 36 degree force in the rope. The x (horizontal) component is parallel to the ice and the old f...

18 years ago

If you want the derivative of the equation you have shown, you should look at the product rule for derivatives. Break this into two functions.

18 years ago

Determine the velocity just as the ball makes first contact with the floor. Determine the velocity as the ball just just leaves the floor. Calculate the delta velocity. Divide this by the delta t to get (delta v)/((delta t) which is average acceleration....

18 years ago

the velocity when the ball first contacts the floor is: V1 = sqrt(2*g*s) V1= sqrt(2 * 9.8(m/s^s) * 1.8m) The velocity when the ball just leaves (rebounds) works the same way except for the distance sign V2 = sqrt(2 * 9.8(m/s^2) * (-1.06m)) V1 - V2= delta...

18 years ago

Area of the rectangle is length * width. Aread of the triangle is 1/2 base * height. The length and width are given. Multiply them to find the area. Take that area to the triangle formula. Area = 1/2 base * height. The base is given. The only unknown is t...

18 years ago

I am guessing that the choice is fractions or decimals. Decimals are easier to see the difference,Suppose one fish is 7 13/16 and the other fish is 7 3/4. Quck! Which is longer?

18 years ago

for x= -4 x^2 is not 8

18 years ago

Add all the money the farmer paid for the horse. Add all the money the farmer got from selling the horse. Did he spend more than he got?

18 years ago

I believe you have it. You said he paid $120. That is correct. You said he spent $140. I think you meant to say he received $140.

18 years ago

You have two velocity vectors that you want to add. For this case, you might want to think of the x axis as the east/west line and the y axis as the north/south line. The jet is moving at 500 km/h due east. There is no y component, just the x component wh...

18 years ago

For exponential notation: You want to express the number as a value greater or equal to 1 and less than 10 multiplied by a power of 10 Examples: 102.4 = 1.024 * 10^(2) 0.00343 = 3.43 * 10^(-3) 17,434 = 1.7434 * 10^(4) So, 20,500 = ?

18 years ago

The domain is the possible values for r. These are given as -1,0,1,2 Using the given equation h(r) = 5r The range is the set of results for a given range. For this case, here are the first two. Domain Range -1 -5 0 0

18 years ago

First I would suggest converting mph to feet/second for both riders. When the second rider passes you, the first rider has been riding for 10 seconds past you. Find that distance (10 seconds * first rider's speed in feet/second). The second rider is catch...

18 years ago

Be sure to take care of units conversions. From L's point of reference, the rain has the x component from her driving plus the y component of the rain falling. Find the resultant vector.

18 years ago

The nice part of the problem is that it states that the rain outside of your apartment is straight down. So, this vector only has a y component. From the problem, it is probably OK to assume that L is driving on a flat highway. So, the vector from the car...

18 years ago

Let x=number of pigs Let y=number of chickens There are two equations with these two unknowns. Assume that the animals have the normal number of heads and feet for their species. Number of heads: x + y = 27 Number of feet: 4 * x + 2 * y = 78 Sove this equ...

18 years ago

If you dropped an object, how long does it take for it to travel 15.4cm? Double this time to account for both the rising and falling motion.

18 years ago

Yes, solve for t for x=15.4cm. For starting at the top, the players initial velocity is 0. So the first term drops out. The calculated time is one half of the total time. Remember that for constant acceleration the time going up is the same as the time go...

18 years ago

for the problem: sin(x) * cos(x) = 0 What values of x will result in cos(x)=0 or sin(x)=0? Hint: in the domain of 0<=x<(2*pi), there are 4 values.

18 years ago

For 60.0 Joules of work force * distance=work force=mass * acceleration (m * a) * distance=work 2kg * g * distance=60.0J substitute the gravitational acceleration for g and solve for distance.

18 years ago

Assuming the car has no kinetic energy at the top... energy at the bottom = energy at the top energy at the bottom = kinetic energy kinetic energy = (1/2) * m * (v^2) So, (1/2)*m*(v^2)=20,000J Solve for v

18 years ago

The velocity is the initial velocity + any velocity based on the acceleration of gravity. Gravity is a negative acceleration to an object thrown upwards. The minimum velocity will be where the ball stops going up and falls back down. Where maximum speed o...

18 years ago

If the velocity is constant, as given, then there is no net acceleration and so no net force. That eliminates two answers.

18 years ago

Yes, you use the jump height to find the initial velocity of the jump. Then,you can use the equation you have shown with the the result, x, being set to 15.4cm. Solve for t. This will give the time in the bottom 15.4cm for the upward motion. The player wi...

18 years ago

You can combine some of the constant acceleration equations to get one that does not have time: (final velocity)^2 = (initial velocity)^2 + (2 * a * s) where: a=acceleration, s=distance

18 years ago

Yes, this might be easier to understand if you think of expressing the perfect square as a product of its square roots. Rearrange to see that the product is a perfect square if x and y are perfect squares: x = a * a y = b * b x * y = a * a * b * b x * y =...

18 years ago

let x=Bill's age, y=Ted's age Bill is two years older than Ted. This gives the first equation: y=x-2 In 5 years, their ages will be: Bill=(x+5), Ted=(y+5) and... 4*Bill's age=5*Ted's age 4*(x+5)=5*(y+5) Use the first equation to substitute for y in the se...

18 years ago

Find a nice common denominator. Multiplying the denominators from the different fractions will always work. In this case, 3 * 8 = 24. Convert 6 2/3 to some number over 24. Hint: 6 2/3 = 160/24 Convert 3 1/8 to some number over 24. Write a fraction where t...

18 years ago

You started correctly, but you must have a math error in the intermediate steps. ((2(x+deltaX)^2 + (x+deltaX) - 1) - (2x^2 + x - 1) )/deltaX =((2x2+4(x*deltaX) + 2deltaX^2 + x + deltaX - 1) - (2x^2 + x - 1) ) /deltaX =(4(x*deltaX) + 2*deltaX^2 + deltaX)/d...

18 years ago

Ooops! the step before the limit statement should have read: 4x + 2deltaX + 1

18 years ago

You are on the right track. The problem states that the company has 36 male employees. I think you intended to say x=60 FEMALE employees. Now you know the number of male employees and the number of female employees. Add the 2 numbers to get the total empl...

18 years ago

Your first two answers look OK. 3rd question: Assuming that all momentum is conserved, the total momentum after the collision is the same as before the collision. The bowling ball is at rest, so no momentum there. The putty has a momentum of 1kg * 1m/s=1k...

18 years ago

Find the speed of light for the laser. How much distance error does 0.19 * 10^-9 represent? Find how far the laser light travels in this time to find the error.

18 years ago

You have the right idea, but made an error early. P=2L+2W, this is correct L=2W-14, this is given So, substituting... P=2*(2W-14) + 2W Solve this for W. Plug the value for W back into the second equation above to find L.

17 years ago

Two items to check: 1. Recall that the light beam strikes the mirror halfway up the mirror. 2. Check which sides/lengths are used to find tan(theta).

17 years ago

You add the forces, but since the force is in opposite directions, they will have different signs. So the result is that you effectively subtract them. The net force will be in the direction of the larger force. The resulting sign of adding two forces jus...

17 years ago

It looks OK.

17 years ago

(a) Recall that: Kinetic energy = (1/2)(m)(v^2) Your formula for kinetic energy is not correct.

17 years ago

W=width L=length given: L = W + 5 Maximum of 180 feet of fencing is available So, 2L + 2W <= 180 Substitute the value for L and solve.

17 years ago

Convert the 50.4 km/h to cm/s. Find the circumference of the 70cm diameter wheel. Use the above values to find revolutions/second. Multiply that by (2)(pi) to find radians/sec.

17 years ago

There is no displacement in the direction of the force. work=force * displacement in the direction of the force.

17 years ago

First, how far did Marla walk? The library is 4 miles. So, the halfway point woud be? Let D be the halfway distance. Time=distance/speed Time = D/(3 mi/h)

17 years ago

Your answer looks OK, but you might want to redo your equation: 50h + 60h = 330. It has no meaning.

17 years ago

1. 30 volts is correct 2. 6.87 is not correct For parallel resistors, 1/RT = 1/R1 + 1/R2 + 1/R3... For two resistors, 4 ohm and 6 ohm 1/RT = 1/4 + 1/6

17 years ago

3. 12 watts is not correct A 4 ohm resistor carrying 3 amps has a voltage drop of 3 * 4 or 12 volts. The current throught the resistor is 3 amps. Volts * Amps = 3 * 12 = 36 Watts. 4. AC voltage is easily changed with a transformer. High voltage is good fo...

17 years ago

Use ohm's law: voltage = current * resistance arranging for current: current = voltage / resistance

17 years ago

Your answer is correct. Be sure to use the units of amps as the current.

17 years ago

amps = volts / ohms = 1.5/1000 amps =0.0015 amps

17 years ago

The unit of currents is amps.

17 years ago

Voltage is measured in volts, current is measured in amps, and resistance is measured in ohms. Ohms law says the relationship between these three items is: V = I * R where V = voltage in volts I = current in amps R = resistance in ohms The equation can be...

17 years ago

That is correct.

17 years ago

U1=(1/2)(37.0)N/cm (3.10cm)^2 U2=(1/2)(18.5)N/cm (s cm)^2 U1=U2 2 * (3.10cm)^2 = (s cm)^2 19.22 cm^2 = s^2* cm^2 s = +- sqrt(19.22) s = +- 4.38cm

17 years ago

Your approach looks OK. Check for any errors in copying the problem or any math errors.

17 years ago

The displacement of the safety spring has to be considered in the total potential energy of the elevator car.

17 years ago

For the roots of the quadratic I got +4.875 -3.854

17 years ago

I just replied to the previous post. The roots I got for the quadratic were +4.875 and -3.854,

17 years ago

f=ma f=force m=mass a=acceleration therefore, m=f/a The values for force and acceleration are given in the problem. Plug them in to get mass.

17 years ago

BobPursley--Thanks for correcting it! I was in too much of a hurry.

17 years ago

Find the cubic meters water volume of the water bed. Do this by multiplying its width * length * height. Water weighs 1000kg/m^3, convert the volume to kg of mass. The force on the floor will be F=m*g. Is this > 6660N ?

17 years ago

A way to solve this type of problem: First express one of the variables in terms of the other. -x-y = 5 or, y = -5-x Now substitute that value for y into the other equation. 2x -(-5-x)=-4 Solve for x, then substitute the known x value into either equation...

17 years ago

The net force on the pilot is just the familiar f=ma. The mass of the pilot is given. The acceleration of the pilot should be the same as the acceleration of the plane. The forumula f=ma can be rearranged to a=f/m. f and m are given for the plane. Solve f...

17 years ago

Usually, the radical sign defaults to mean the squres root. So, the question is for what values of x is the square root of (2x-10) a real number. The square root is real for all non-negative values. So, for what values of x will (2x-10) be non-negative? W...

17 years ago

I get a different answer for acceleration. Check your conversion from 57.0 km/hr to ?? m/s.

17 years ago

square both sides, collect like terms and solve. Here's the first step: (k+3)^2 = (2k-1)^2 k^2 + 6k + 9 = 4k^2 - 4k + 1 Combine all the like terms. You might factor it out, but I would suggest using the quadratic equation.

17 years ago

I don't think you copied the first question correctly. Did you intend 2 equal signs?

17 years ago

Also, because of the (p+1) term remember that p=-1 will be a solution.

17 years ago

Hint. Each term on both sides has a factor (p+1). Divide all terms on both sides by (p+1). This will simplify it for you.

17 years ago

Find the potential energy given to the object when the rope is pulled to the side. This is just the height difference. The new distance from the ceiling is 1.5m * sin(35). The original distance was just the rope length (1.5m). Use mgh for the potential en...

17 years ago

Area of a triangle: Area=(base * height)/2 Area of a trapezoid: Area=height * (b1 + b2)/2 where: b1=length of top side b2=length of bottom side

17 years ago

Integer coeffecients means numbers with no decimal part. Recall that an equation is still valid if you multiply both sides by the same value. For the coeffecients of X (6.2 on the left and 3.8 on the right) what would be required to change those to 62 and...

17 years ago

To find the actual tablespoons per serving, divide the total tablespoons used by the total servings: (3 tablespoons)/(1.5 servings) =3/1.5 tablespoons/serving =?? tablespoons/serving

17 years ago

let x = speed of first part of trip in mph let x-5 = speed of second part of trip in mph 5 hours = 63 miles/x + 6/(x-5) Solve for x. If you solve a quadratic, ignore the answer which would cause the slower speed to be negative (non-real case).

17 years ago

The first problem: Sketch this problem to make it easier to visualize. There is a rectangular frame with the inside dimensions of 12 * 16 inches. The frame has a width of W. You need to divide the frame into pieces and then write an equation for those pie...

17 years ago

Sorry, the diagram didn't survive the font change.

17 years ago

point A f(x) = 1/(x^2) point B f(x+deltaX) = 1/((x+deltaX)^2) The slope of the line between these points is: [f(x+deltaX) - f(x)]/[(x+deltaX - x] The slope of the tangent is given when deltaX->0. to get you started... [(1/(x+deltaX)^2) - 1/x^2]/[x+deltaX...

17 years ago

(x + a ) (x + b) = x^2 + 7x + 10 Think what two number multiplied give 10, and when added give 7?

17 years ago