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?

0.66 m/s

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:

b. latent learning (the word "latent" itself means something that exists but isn't obvious, only under certain conditions! )

real, smaller and upside-down.   so the answer should be b.