How does mass effect potential and kinetic energy on a roller coaster?

Acar's position in relation to time is plotted on the graph. what is the car's average velocity? a) 5 m/s b) 10 m/s c) 30 m/s d) 50 m/s

The system is released from rest with the cable taut, and the homogeneous cylinder does not slip on the rough incline. determine the angular acceleration of the cylinder and the minimum coeffi cient s of friction for which the cylinder will not slip.

What’s #16 asking me and how do i solve it?