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
