Determine the magnitude of the frictional force (in N) acting on a 15.0 kg crate in the following scenarios. Include a free-body diagram for each scenario.. a. When the crate is moving at a constant velocity on a horizontal surface with a coefficient of kinetic friction of 0.3. b. When the crate is resting on a surface inclined at 25° relative to the horizontal, with a coefficient of static friction of 0.6. c. When the crate is at rest in the back of a truck that is accelerating forward at 3.0 m/s2 , with a coefficient of static friction of 0.5. d. When the crate is being pushed with a horizontal force of 120 N on a level surface, and the coefficient of kinetic friction is 0.25. Calculate the acceleration of the crate as well.