1. In ALL types of collisions, the total momentum is ALWAYS conserved.

Choose the correct word that describes the type of collision in each sentence:

a. In elastic collisions, the total kinetic energy is conserved / decreases.

b. In inelastic collisions, the total kinetic energy is conserved / decreases.

c. In elastic and inelastic collisions, the objects separate/stick after a collision.

d. n perfectly inelastic collisions, the objects separate/stick after a collision.

2. How much work is done to lift a 300 N child a vertical distance of 1.5 m at a constant speed?

3. A block of mass 3.0 kg is placed against a horizontal spring of constant k 5,875 N/m and pushed so the spring compresses by 0.07 m. If the block is released and the surface is frictionless, calculate the block's speed after leaving the spring.

4. A man claims he can safely hold on to a 12.0 kg child in a head-on collision with a relative speed of 53.6 m/s lasting for 0.10 s as long as he has his seat belt on. Find the magnitude of the average force needed to hold onto the child.