A shopper pushes a grocery cart for a distance 18 m at constant speed on level ground, against a 25 N frictional force. He pushes in a direction 24° below the horizontal.

Question

A shopper pushes a grocery cart for a distance 18 m at constant speed on level ground, against a 25 N frictional force. He pushes in a direction 24° below the horizontal. 
What is the work done on the cart by the shopper, in joules? Magnitude of the force, in newtons, that the shopper exerts on the cart? What is the total work done on the cart, in joules?

Henry · Answer

Fx - Fk = M*a Fex*Cos24 - 25 = M*0 = 0 Fex*Cos24 = 25 Fex = 27.4 N. = Force exerted Work = Fx*d = 27.4*Cos24 * 18 = 450.6 Joules