Carlota does 2000 J of work on a machine. The machine does 500 J of work. What is the efficiency of the machine?

4%

25%

75%

400%

What evidence shows that the burning of methane is a chemical reaction?

A golf ball is dropped from rest from a height of 9.50 m. It hits the pavement, then bounces back up, rising just 9.70 m before falling back down again. A boy catches the ball on the way down when it is 1.20 m above the pavement.

An eclipse of the moon is caused by the A. curvature of the moon. B. moon's shadow. C. curvature of the sun. D. Earth's shadow

A student adds two numbers together. How can the student determine the number of significant figures in the answer? A student measures her height with a meter stick and finds that she is about 1.5 m tall.

A horse pulls a cart along a flat road. They start from rest and as time goes on their speed increases.

1. For a reaction to occur, energy must be to break chemical bonds. O A released OB converted OC absorbed

51 Mm is how many km?

What type of change occurs when water changes from solid to a liquid

Definition of artficial and natural radioactivity

In order for an object to conserve it's total mechanical energy it is absolutely necessary that?