2.   A person pushes a 20-kg lawn mower at constant speed with a force of 120 N directed along the handle, which is at an angle of 55o to the horizontal (see figure).

a.  (4 points)
Draw the free-body diagram showing all forces acting on the mower.
 
 
 
 
 
 
 
 
 
 
 
 
 

b.  (7 points)
Calculate the horizontal retarding force on the mower.
 
 
 
 
 
 
 
 
 
 
 

c.  (7 points)
Calculate the normal force exerted vertically upward on the mower by the ground.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

d.  (7 points)

Calculate the force the person must exert on the lawn mower to accelerate it from rest to 1.0 m/s in 3.0 seconds (assuming the same retarding force).