Question

A person with mass mp=80 kg is standing at rest on a horizontal, frictionless surface holding a ball of wet clay with mass mg=10 kg . In front of the person is a large block with mass M=20 kg at rest next to a spring with stiffness k=100 N/m . The person throws the ball horizontally, it sticks to the block, and then ball and block slide and compress the spring a distance 1=0.75 m away from equilibrium before the ball-block springs back toward the person. (Assume the distance the ball is thrown is short, so that we can ignore the vertical component of its velocity.)

a) Draw the following moments in time with the given labels: At t=0, the person is holding the ball and all objects are rest. At t=1 the ball has left the person's hands. At t=2 the ball and block move together with speed V2. At t=3; the ball and block have fully compressed the spring. At t=4 the ball and block are sliding back toward the person, At t=5 the person, the ball, and the block are all moving together, HINT: Include a coordinate system! Remember that momentum is a VECTOR and energy is a SCALAR.

b) Find V2 (the speed of the ball and the block just before they start compressing the spring)

c) Find VB. (the speed of the ball after it was thrown, but before it hits the block)

d) Find Vp (the speed of the person after the ball was thrown)

e) Find Vs (the speed at which the person, ball, and block move after the ball and block bounced back off the spring and collided with the person)

f) If it takes 0.2 seconds for the person and the ball-block to get to the same velocity, find the impulse on the person due to the ball-block. AND find the force on the person due to the ball-block,

Answer 1