Calculate the work done by gravity as a 5.6 kg object is moved from A to B in the figure(Figure 1) along paths 1 and 2. Enter your answers numerically separated by commas

Question

https://session.masteringphysics.com/problemAsset/2326540/2/Walker.8.4.jpg

Answer 1

W = (F cos θ)s where

F = force = mg = (5.6 kg)(9.8 m/s²) = 54.88 N

θ = the angle between the direction of the force and the direction of movement

s = displacement

Path 1: W = (54.88)(cos 90°)(5) + (54.88)(cos 0°)(1) = 0 + 54.88 = 54.88 J

Path 2: W = (54.88)(cos 0°)(1) + (54.88)(cos 90°)(5) = 54.88 + 0 = 54.88 J

(Each answer is W = 55 J if you're required to have the correct number of significant figures.)

because cos 90° = 0, on the parts of the path with θ = 90° gravity does no work.

Note that the path taken from A to B has no effect on the work done by gravity. The only thing that matters is the net vertical displacement. A simpler way to calculate work done by gravity is:

W = mg(h₀ – h_f)