Question

In class I mentioned that we used to show an actual ballistic pendulum where a rifle is shot into a heavy block to see how the block moves. Assume a 4.7 gram bullet is fired at 678 m/s into a 4.8 kg block of wood. The block hangs from a long string to approximate 1D motion. How fast does the block move just after the collision in m/s?

Answer 1

0.66 m/s

Step-by-step explanation:

This is an inelastic collision, for that reason the conservation of momentum law allows us to determine the final velocity of both, the bullet and block together after the collision:

`m_(bullet) v_(bullet0) +m_(block) v_(block) =(m_(bullet)+m_(block))v_(f) \\v_(f) =(m_(bullet) v_(bullet0) )/(m_(bullet)+m_(block)) \\v_(f) =(0.0047kg*678m/s)/(4.8kg+0.0047kg)\\v_(f) =0.66 m/s`