physics help!?

Question

1. can the amount of energy in the universe ever increase?why?

2.pushing a cart down the hall that was initally at rest imcreases its kinetic energy but where did the energy come from?

3.explain an energy transformation that you might use every day?

4.what two types of energy are considered mechanical energy?

5.when a driver presses on the brakes of a car where dose all the energy go?

6.how fast would a 4kg mass have to be going to get to a height of 20 meters?

plz help so confused!

Answer 1

1. Not if you believe the first law of thermodynamics.

2. It came from whomever did the pushing. He had to spend some chemical potential energy from his body.

3. Burning something, converting electricity to music, you could easily name thousands.

4. I hate stupid questions like this. Tell your teacher I said he or she is giving stupid HW. But the answer wanted is probably potential and kinetic.

5. The brake pads heat up. The heat is dissipated into the air.

6. You need to work at least a little for this one.

PE = mgh KE = 1/2 mv^2. Set them equal. Solve for v. You know g. You are given h. Notice how m doesn't even matter, even though it is given.

Answer 2

1. Energy is never created or destroyed, it is only reformed.
2. The energy comes from the energy you used to push it, for every action this is a equal and opposite reaction.

as for the others, i will be back later to answer...