A shopper pushes a grocery cart for a distance of 18m at a constant speed on level ground, against a 37.5N frictional force. he pushes in a direction 27.5° below the horizontal.

what is the work done on the cart by gravitational force, in joules.

d = distance to which the grocery cart is pushed = 18 m

f = frictional force = 37.5 N

θ = angle of force below the horizontal = 27.5 deg

W = gravitational force in downward direction

Θ = angle between gravitational force in down direction and displacement in horizontal direction = 90

U = work done on the cart by gravitational force

work done on the cart by gravitational force is given as

U = W d CosΘ

inserting the values

U = W (18) Cos90

U = 0 J