A person pushes a 16.0-kg shopping cart at a constant velocity for a distance of 20.0 m. She pushes in a direction 28.0° below the horizontal. A 54.0-N frictional force opposes the motion of the cart.

Answer 1

Wc = m * g = 16kg * 9.8N/kg = 156.8 N. = Wt. of the cart.

Fe*cos28-Ff = m*a
0.8829Fe - 54 = m*0 = 0
0.8829Fe = 54
Fe = 61.2 N. = Force exerted.

W = Fe*cos28 * d
W = 61.2*cos28 * 20 = 1080 Joules = Work
done on cart.