Question

A 7.00 g bullet, when fired from a gun into a 0.80 kg block of wood held in a vise, penetrates the block to a depth of 8.20 cm. this block of wood is next placed on a frictionless horizontal surface, and a second 7.00 g bullet is fired from the gun into the block. to what depth will the bullet penetrate the block in this case?

Answer 1

To determine the depth to which the second bullet will penetrate the block, we can use the work-energy theorem. By comparing the initial kinetic energy of the bullet-block system to the work done by the average stopping force in each situation, we can find the depth.

Step-by-step explanation:

The initial situation is when a 7.00 g bullet is fired into a 0.80 kg block of wood held in a vise. The bullet penetrates the block to a depth of 8.20 cm. In the second situation, the block of wood is placed on a frictionless horizontal surface, and a second 7.00 g bullet is fired into the block. The question asks to determine the depth to which the bullet will penetrate in this case.

To solve this problem, we can use the work-energy theorem. Since the wood block is on a frictionless horizontal surface, there is no external force doing work on the block-bullet system. Therefore, the initial kinetic energy of the bullet is equal to the work done by the average stopping force in stopping the bullet. We can equate these two and solve for the unknown depth.

In the initial situation, the bullet penetrated to a depth of 8.20 cm. We can use this known value along with the mass of the bullet and the mass of the block to find the initial kinetic energy of the bullet-bloc system. Then, we can set this initial kinetic energy equal to the work done by the average stopping force in the second situation to find the depth to which the bullet will penetrate.

Answer 2

The 7.00 g bullet, if fired from the gun into the block, would more then likely penetrate less then 4.10 cm. The vase was holding the block in place at first, but with it now placed on a frictionless surface the block will not be held in place as well and will glide much easier because of it.