Question

Lester in the PE department is pushing an 88.4-kg load of towels at a constant speed a distance of 23.7 meters using a horizontal force of 179 newtons. Determine the work done by friction.

a) 0 J (joules)
b) Positive work
c) Negative work
d) Not enough information to determine

Answer 1

The work done by friction is negative because it is in the opposite direction to the motion, with a magnitude of -4245.3 joules, so the right answer is (c) Negative work.

Step-by-step explanation:

To calculate the work done by friction, we need to understand that work is defined as the product of force and the distance over which it acts, when the force and distance are parallel. The work done by friction is negative because it is in the opposite direction to the motion, with a magnitude of -4245.3 joules, so the right answer is (c) Negative work.

Since Lester is pushing the load at a constant speed, this implies that the net force on the load is zero, and hence the force of friction must be equal in magnitude and opposite in direction to the applied force of 179 newtons. The work done by friction would be the product of the frictional force and the distance, which gives -179 N × 23.7 m = -4245.3 J.

The negative sign indicates that the work done by friction is in the opposite direction of the motion. Therefore, the correct answer is (c) Negative work.