What is the equation for calculating a machine's efficiency?

I searched all over my textbook and couldn't find it, so I decided to post my question here.

A vertically hung spring has a spring constant of 150. newtons per meter. A 2.00-kilogram mass is suspended from the spring and allowed to come to rest. 72-73 Calculate the total elastic potential energy stored in the spring due to the suspended 2.

A car veers off course and runs straight into a brick wall. This is an example of which of the following? A. long time, large force B. long time, small force C. short time, small force D. short time, large force

The rate at which work is done or energy is used is referred to as what

Surface currents and waves are powered by what

A car climbs 10.0 kilometers up a hill that inclines 8.0 degrees. What is the car's vertical displacement?

An apple falls from an apple tree growing on a 20° slope. the apple hits the ground with an impact velocity of 16.5 m/s straight downward. what is the component of the apple's impact velocity parallel to the surface of the slope?

Objects falling through the air experience a type of friction called air resistance. true or false

How big is a wifi pulse signal coming from your router? A) 10 meters B) 15 meters C) 5-10 meters D) 20-30 meters

Imagine you are in a music concert. What different sounds might you hear? How are these sounds made?

Dose aloe Vera grow in the mesa?