Question

A girl rides her bike 5.1 km due east. While riding she experiences a resistive force from the air that has a magnitude of 2.8 N and points due west. She then turns around and rides due west, back to her starting point. The resistive force from the air on the return trip has a magnitude of 3.2 N and points due east.(a) Find the work done by the resistive force during the round trip.

Answer 1

Answer:

The work done by the resistive force during the round trip is -30,600 J

Explanation:

A round trip is to and fro.

To:      5.1 km →     ← R₁ = 2.8 N

Fro:     → R₂ = 3.2 N     ← 5.1 km

5.1 km = 5,100 m

∴ Work done = -2.8 x 5,100 -3.2 x 5,100

                      = -14,280 - 16,320

                      = -30,600 J