Question

1. Can effeciency ever exceed 100%? Explain.

2. For an inclined plane, what is the effect on efficiency as the angle increases?

Answer 1

effieciency = output work/ input work

A simple machine will have an efficiency of 100% if the output work of the machine is equal to the work input.

The output work can't be greater than the input work because of the friction that occurs. The input work is divided by the output work and "losses" due to friction.

hence efficiency never exceed 100%

answer is NO

(2)

As the angle of inclined increases , the normal force acting on the inclines plane decreases theremore force of frction decreases

n the inclined plane

Fy = 0

N - mg cos theta = 0

N = mg cos theta

friction force = f= u N = u mg cos theta

cos theta value decreases when angle increases so frction force decreses . object doing more output work

so effieciency increases