Question

Trevor is pulling his younger brother in a wagon. He pulls the wagon 50 m to the corner with a force that is a parallel with the ground. He then turns the wagon around and pulls it 50 m back to the starting point with the same force at an angle of 30 degrees with respect to the ground. How does the amount of work Trevor performs going to the corner compare with the amount of work he performs coming back?
A) they are the same because he uses the same amount of force
B) they are the same because he travels the same distance
C) he does less work coming back because the force moving the wagon is only 50cos30
D)he does more work coming back because the force moving the wagon is only 50cos60

Answer 1

The answer is C I just took the quiz & got 100%

Answer 2

Work has the greatest value when the force done is parallel to the direction of motion. In this case, the work done in pulling the wagon to the corner is greater than the amount of work done in pulling the wagon back to the starting point. This is because an angle of 30 degrees is applied when pulling it back. The formula for work when angle is applied is:

Wx = W cos θ

Where in this case, θ = 30

Therefore, the answer to this is letter:

C) he does less work coming back because the force moving the wagon is only 50cos30