Which of the following is the best example of potential energy? a ball sitting at the top of a hill a ball sitting at the bottom of a hill a ball rolling down a hill

There is no air in space astronauts in space cannot hear sounds from outside their spacesuits explain this

What are the three main phases of matter and how are the particles aligned

A cat is being chased by a dog. Both are running in a straight line at constant speeds. The cat has a head start of 3.8 m. The dog is running with a speed of 8.9 m/s and catches the cat after 6.0 s. How fast did the cat run?

Starting from rest, the boy runs outward in the radial direction from the center of the platform with a constant acceleration of 0.5 m/s2. The platform rotates at a constant rate of 0.2 rad/s. Determine his velocity (magnitude) when t = 3 sec

What happened to Sound if the frequency of the vibrations increases

What is the energy source that heats a contracting protostar?

What unit is kg divided by m/s^2

If the energy stored in the fully charged battery is used to lift the battery with 100-percent efficiency, what height is attained? Assume that the acceleration due to gravity is 9.8 m/s2m/s2 and is constant with height

How does the mass of an astronaut change when she travels from earth to the moon? how does her weight change?

If an object has a mass of 20 grams and a volume of 40 cm3, what is its density in g/cm3?