Answer:
a = F-ff/m
Explanation:
According to Newton's second law of motion which states that "the rate of change in momentum of a body is directly proportional to the applied force F and acts in the direction of the force.
Mathematically;
F = ma
Since two forces acts on the cart i.e the moving force F and the frictional force Ff , we will take the sum of the forces.
∑F = ma where
m is the mass of the cart
a is its acceleration
∑F = F+(-ff )(since frictional force is an opposing force)
F - ff = ma
Dividing both sides by mass m
a = F-ff/m
It’s c because it’s not Control so that means that it would be broken and non fix able
Answer:
(a) -472.305 J
(b) 1 m
Explanation:
(a)
Change in mechanical energy equals change in kinetic energy
Kinetic energy is given by
Initial kinetic energy is 
Since he finally comes to rest, final kinetic energy is zero because the final velocity is zero
Change in kinetic energy is given by final kinetic energy- initial kinetic energy hence
0-472.305 J=-472.305 J
(b)
From fundamental kinematic equation

Where v and u are final and initial velocities respectively, a is acceleration, s is distance
Making s the subject we obtain
but a=\mu g hence

The answer should be d because they are constantly rotating