Phys-100 momentum techniques and constant acceleration equations
You should make use of momentum techniques to solve these problems. Be sure to include a properly labeled diagram along with your solutions for each of the problems. The diagrams will be worth a point or two, so please don’t forget them. Tiny little diagrams without numerical labeling will not receive any credit. Also, when dealing with vector quantities remember to adopt a sign convention! Stating your sign convention will also be worth a point, so please remember to include this as well!Feel free to do your work by hand and then insert a jpeg directly into this document for each question. Make sure your images are nicely sized and positioned. Only Word documents will be accepted.
1.Two gliders are moving on a long, frictionless track (similar to the one I used in class with the sail cart demonstration right before spring break). The first glider of mass is initially traveling to the right with a speed of . A second glider of mass is initially traveling to the left with a speed of . The two gliders have a perfectly elastic collision. After the collision, the second glider rebounds to the right with a speed of . (17 points)
A)Determine the magnitude and direction of the velocity of glider #1 after the collision.
B)What is the impulse suffered by each glider during the collision? Note that you must show a calculation for each glider.
C)If during the collision the gliders remain in contact for 112.9 milliseconds, determine the average force exerted by each glider on the other . Note that you must show a calculation for each glider. Watch your signs!
2. A volleyball is dropped to the ground from a window at a height of above the ground. The ball makes a perfectly elastic collision with the ground.
A)Neglecting air resistance, determine the impulse give to the ball by the ground.
B)If the ball was in contact with the ground for 5.17 milliseconds, determine the average force exerted by the ground on the ball.
C)Now assume that instead of bouncing, the ball when dropped from the same height lands in some wet cement. The center of mass of the ball moves through a vertical distance of into the cement before coming to a complete stop. Determine the impulse given to the ball and the average force exerted on the ball by the wet cement. Be sure to use momentum/impulse techniques here and not Newton’s 2nd Law.
3. A quarter is dropped from the top of the Sears building in Chicago and lands on the head of a person that is a distance of below. Just before the quarter hits the person’s head, it is falling at a speed of . The quarter comes to a complete stop in the person’s head after penetrating a distance of . (14 points)
A)Determine the acceleration of the quarter as it strikes the head (i.e. this will be a deceleration as the quarter will stop upon hitting the head).
B)Calculate the average force of the head on the quarter using momentum techniques.
C)Recalculate the average force of the quarter on the head using Newton’s 2nd Law.
D)Parts of the skull bone will be fractured by forces of about or more. Is there a chance of this person’s skull being fractured by the quarter? Explain.
