A spring is compressed so that it has 7.2 J of elastic potential energy. A 0.3 kg ball is placed on top of the spring. When the spring is released how high will the ball go?

A spring has a spring constant of 75N/m. The spring is compressed15cm and a 2kg ball is attached to the spring in its compressedstate.

a. When the spring is released, what is the kinetic energy of theball as it leaves the spring?

b. What is the potential energy of the spring in its compressedstate?

c. What is the potential energy of the spring as the ball leavesthe spring?

d. What is the total energy of the system (ball and spring) whenthe spring is compressed?

e. What is the total energy of the system (ball and spring) whenthe ball leaves the spring?

I know, its a lot of questions but I have no idea how to work onit. I have a few equations, but I have no idea how to apply them.:
U=mgy (potential difference = mass*gravity*y displacement)
K=.5mv^2 (Kinetic energy=.5*mass*velocity^2)

In a toy, a 92.4 g ball rolls into a spring and compresses the spring. If the ball is rolling at 4.28 m/s when it collides with the spring and, at maximum compression, the spring is storing 0.560 J of elastic potential energy, with what efficiency is the ball’s kinetic energy converted into elastic potential energy of the spring?

What is the spring constant of a spring that is compressed 0.2 m and has 1.50 J of elastic potential energy stored in it?