Two object (mass a & b) are connected by a light string that passes over a frictionless pulley. the object (mass b) is held at rest on a fixed incline of angle = 40 and mass b is left hanging at rest above the floor. the objects are released from rest and mass a slides 1m down the incline in 4s. draw the free body diagram of the objects mass a and b

We study the movement of each body separately. For the mass body A: vector: T + Na + Ga + Ff = ma * a.Scalar: on the axis Ox: ma * g * sinα-T-Ff = ma * a

On the axis Oy: Na-ma * gcosα = 0=>Na=ma * g*cosα

Ff=μ*N=μ*ma * g*cosα

ma * g * sinα-T-μ*ma * g*cosα=ma*a

For mass body B: vector: Gb + T = mb * a.Scalar: by projection of the vector relation on the axis Ox:T-mb*g=mb*a

answer would be letter choice (a),   a ball resting on a shelf. would be another example of potential energy   >   stored energy > not moving.

a ball spinning on a finger   >   kinetic energy > moving energy

a ball rolling on the ground   >   kinetic energy   > moving energy

a   ball flying through the air   > kinetic energy   >   moving energy

hope that                                         : )