A train travels 68 kilometers in 4 hours, and then 91 kilometers in 2 hours. What is its average speed?

What form of matter is vapor? a solid made of a substance that is usually liquid a liquid made of a substance that is usually gas a gas made of a substance that is usually solid a gas made of a substance that is usually liquid

What would happen to the moon if earth stopped exerting the force of gravity in it

Which of the following machines most likely has the greatest efficiency? a A. Airplane B. Automobile C. Bicycle D. Human body

What does a machine change to make work easier?

What is the mass number of a potassium atom that has 20 neutrons

A raindrop has a mass of 5.4 * 10-7 kg and is falling near the surface of the earth. Calculate the magnitude of the gravitational force exerted (a) on the raindrop by the earth and (b) on the earth by the raindrop.

As an astronaut travels towards Earth, her weight A. decreases because gravity decreases. B. decreases because her mass decreases. C. increases because gravity increases. D. remains the same because her mass remains the same.

Lightning often strikes water. a. True b. False

How much work must be done on a 10 kg snowboard to increase its speed from 4 m/s to 6 m/s?

If a spacecraft that seems to be motionless in deep space is given some type of quick push, what will happen? A. The spacecraft will not move because it only works on earth. B.