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.

Andrew lifts a table 7 meters from the ground floor of her house to his attic. If the table weighed 20 kg, what is the gravitational potential energy gained by the table? Estimate g as 9.81. 1300 O 1400 1500 J 1600J 1700

Which of these is an example of a mechanical wave? Ocean waves Microwaves used to heat food X-ray Light from a flashlight

If you needed to find the force needed to pull a small car up a ramp it would be best to use - A. A spring scale B. An electronic balance C. A triple beam balance D. A formula

The gravitational force between two giant lead spheres is 0.010 N when the centers of the spheres are 20 m apart. What is the distance between their centers when the gravitational force between them is 0.160 N?

What happens to the particles of the liquid inside a thermometer when the thermometer is heated? They slow down and spread apart. They speed up and spread apart. They slow down and move closer together. They speed up and move closer together.

What happens to the period of a pendulum and the period of a spring as the amplitude of the oscillation increases? Briefly give an explanation for this relationship.

The element that is most abundant in earth is

Your car travels 600 miles in 6 hours. You stop the car for lunch for 1 hour and then you continue on your trip for another 14 miles and finish the entire trip in 8 hours. What was your car's average speed while you were driving?

Speed is a vector quantity

The observation location A is located at m. The conventional current running through the wire is 7.5 amperes. In this exercise you will calculate the magnetic field at the observation location due only to segment 4 of the wire.