posted by johhnny .
A person pushes a 24.7-kg shopping cart at a constant velocity for a distance of 34.0 m on a flat horizontal surface. She pushes in a direction 23.2 ° below the horizontal. A 48.5-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. F*cos23.2-48.5 = m*a = m*0 = 0
Fcos23.2 = 48.5
F = 48.5/cos23.2 = 52.8 N.
b. Work = F*d = 52.8 * 34 = 1795 Joules.
c. Work = Fk * d = 48.5 * 34 = 1649 J.