3. A 3 kg block of lead is slowly placed on top of a spring with a spring constant of 800 N/m. (a) By how much does the spring compress when the lead block is placed on top of it? (b) A 1.5 kg block of iron is dropped on top of the lead block from a height of 2m above it. How fast is the iron block traveling just before it hits the lead block? (c) When the iron block collides with the lead block, it becomes stuck to the lead block. How fast are the two blocks traveling just after they collide? (d) After the two blocks collide, what is the farthest the spring compresses before the blocks are pushed back up