Question

A girl rides her bike 5.6 km due east. While riding she experiences a resistive force from the air that has a magnitude of 2.7 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 and ints due east. (a) Find the work done (in J) by the resistive force during the round trip. (b) Based on your answer to part (a), is the resistive force a conservative force? Yes No Additional Materials Reading

Answer 1

1. Here, in this question we have to find net work done by resisting force on round trip of girl

Firstly, when girl go from west to east , here resisting force is in opposite direction.

As per work done formula - Force * Displacement* cos(theta)

W₁ = 2.7*5.6*1000*cos(180)

W₁ = −15120 Joule

Now, while moving from east to west

then, W₂= 3.1*5.6*1000*cos(180) = −17360 Joule

Now, total Work done is = W₁+W₂ = −15120−17360 = −32480 Joule

2. Based on above question this resisting force is not conservative force because on round trip the work done is not zero, so this force is not conservative