(II) A person pushes a lawn mower at constant speed with a force of directed along the handle, which is at an angle of to the horizontal (Fig. . (a) Draw the free-body diagram showing all forces acting on the mower. Calculate (b) the horizontal friction force on the mower, then (c) the normal force exerted vertically upward on the mower by the ground. ( ) What force must the person exert on the lawn mower to accelerate it from rest to in seconds, assuming the same friction force?

Solution 26P: We have to calculate the forces exerted on lawn mower and the forces exerted by the lawn mower under the given situation. Step 1 of 5 Concept: 1) Newton’s third law: To every action there is an equal and opposite reaction. 2) Newton’s second law: The force F acts on mass m produces an acceleration a in the object. Mathematically, F=ma. 3) Frictional force also acts on the surface of the bodies in contact whenever their is relative motion between between the two bodies. 4) Free body diagram of a body gives the diagrammatical representation of all the forces acting on the body in terms of magnitude and diagram, under the given situation.