posted by Anonymous on .
A person pushes a 19.5-kg shopping cart at a constant velocity for a distance of 35.6 m on a flat horizontal surface. She pushes in a direction 25.4 ° below the horizontal. A 53.1-N frictional force opposes the motion of the cart. (a) What is the magnitude of the force that the shopper exerts? Determine the work done by (b) the pushing force, (c) the frictional force, and (d) the gravitational force.
a. Fap*cos25.4 - Ff = m*a.
Fap*cos25.4 - 53.1 = 19.5*0 = 0 Fap*cos25.4 = 53.1
Fap = 53.1/cos25.4 = 58.8 N. = Force applied by shopper.
b. Work = Fx * d=58.8*cos25.4*35.6=1891 Joules.
c. Work = Ff*d = 53.1 * 35.6 = 1890 J.