There is a limited amount of fossil fuels (our main source of energy for powering our appliances and cars) on Earth. Why? What is an example of a "renewable" energy source, and why is it considered "renewable"?

According to newton’s first law of motion, which force is expected to cause a body to accelerate?

The great sandini is a 60.0-kg circus performer who is shot from a cannon (actually a spring gun). you don’t find many men of his caliber, so you him design a new gun. this new gun has a very large spring with a very small mass and a force constant of 1100 n/m that he will compress with a force of 4400 n. the inside of the gun barrel is coated with teflon, so the average friction force will be only 40.0 n during the 4.00 m he moves in the barrel. at what speed will he emerge from the end of the barrel, 2.50 m above his initial rest position?

A51 kg woman skis down a hill and her kinetic energy is 9.96e4 j. what is her speed?