Question:

You shoot a 0.0050-kg bullet into a 2.0-kg wooden block at rest on a horizontal surface (Figure 1) . After hitting dead center on a hard knot that runs through the block horizontally, the bullet pushes out the knot. It takes the bullet 1.0 ms to travel through the block, and as it does so, it experiences an x component of acceleration of -4.9 ×105 m/s 2. After the bullet pushes the knot out, the knot and bullet together have an x component of velocity of +10 m/s The knot carries 10% of the original inertia of the block.

Part A

What is the initial velocity of the bullet?

500 m/s

Part B

Using conservation of momentum, compute the final velocity of the block after the collision.

Express your answer with the appropriate units.

v block,f = 

Part C

Calculate the initial kinetic energy of the block-knot-bullet system.

Express your answer with the appropriate units.

Ki= 

Part D

Calculate the final kinetic energy of the block-knot-bullet system.

Express your answer with the appropriate units.

Kf =