Homework - 1/10/11

The Pitfall at Kennywood lifts riders to the top of the tower, 76 meters above the ground, and releases them from rest. Using the law of conservation of energy, determine the speed of the riders just before reaching the bottom. (For those of you that have actually been on the Pitfall, you may remember that you actually begin slowing down about two-thirds of the way down. Let's ignore the slowing and just assume that the riders stop at the very bottom.)

Remember: For full credit, you must fill the entire page. Draw a quick diagram of the situation and list the initial and final positions. List the givens, show all of your work, and circle the final answer. Also, explain whether your answers seem reasonable.

Homework - 12/6/10

Two air track gliders collide with each other as shown. Let M = 1 kg. Glider A is moving to the left with an initial speed of 5 m/s and glider B is initially at rest.

a. If glider A collides elastically and has a final speed of 2.5 m/s, how fast is glider B moving?
b. If glider A collides inelastically, what is the final speed of each glider?


Remember: For full credit, you must fill the entire page. List the givens, show all of your work, and circle the final answer. Also, explain whether your answers seem reasonable.

Homework - 11/15/10

1. A bullet with a mass of 0.004 kg is fired from a rifle with a speed of 960 m/s. How fast would the average person have to run in order to have the same momentum as the bullet? The average mass of an adult is 70 kg.

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2. Explain one other situation where the bullet and the person have the same momentum.

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Remember: For full credit, you must fill the entire page. List the givens, show all of your work, circle the final answer. Also, explain whether you think a person could actually reach that speed to have the same momentum as the bullet.

Homework - 10/18/10

Two blocks are tied together and hung from the ceiling by two strings as shown above. The mass of the upper block is 2 kg and the lower block is 1 kg. Determine the tension in each string.

Remember: For full credit, you need to fill the entire page. You must include the free body diagram, show all of your work, and explain if your answer seems reasonable or not.

Homework - 10/14/10

Three bears each push on a 25kg crate full of kittens with 100 N. Kitten lover and long-time bear hater, Mr. Aul steps in to the rescue. Mr. Aul pushes back with 500 N. What is the magnitude and direction of the crate's acceleration?

Remember: For full credit, you need to fill the entire page. You must include the free body diagram, show all of your work, and explain if your answer seems reasonable or not.

Homework - 10/4/10

An arrow is fired from a bow with an initial speed of 100 m/s at an angle of 40 degrees.

a. Determine how much time the arrow spends in the air.

b. Determine the maximum height reached by the arrow.

Remember: For full credit, you need to include the diagram, mathematics, and explanation to fill the entire page. For the explanation, remember to explain how you knew which equation to use and whether your answer seems reasonable.

Homework - 9/29/10

A projectile is launched from the ground at an angle of 37 degrees with an initial velocity of 50 m/s.

(a) Calculate the total time for the projectile to hit the ground.

(b) How far away will the projectile land from where it was launched?

Remember: For full credit, you need to include the diagram, mathematics, and explanation to fill the entire page. For the explanation, remember to explain how you knew which equation to use and whether your answer seems reasonable.