What law states that when matter undergoes a physical or chemical change, no atoms are created or destroyed?

If she wants to bike 220 km, how long (in hours) must she ride? a cyclist rides at an average speed of 25 miles per hour.

José is pinned against the walls of the Rotor, a ride with a radius of 3.00 meters that spins so fast that the floor can be removed without the riders falling. When the ride accelerates to a speed of 17.0 m/s, his angular momentum is 3570 kg m2/s.

The earth exerts a force of 1.00 N on an object in free fall. What is the object's mass?

A shallow hole is dug and lined with concrete. A number of large black plastic bags, each filled with several centimeters of water, are placed in the hole and then covered with fiberglass insulation panels.

How much work does a 65 kg person climbing a 2000 m high cliff do?

A body with v=20m/s changes its speed to 28m/s in 2sec. its acceleration will be

Charge: A piece of plastic has a net charge of + 2.00 μC. How many more protons than electrons does this piece of plastic have? (e = 1.60 * 10-19 C)

How much heat is needed to raise the temperature of 6g of water by 18oC?

A proposed space station includes living quarters in a circular ring 50.0 m in diameter. At what angular speed should the ring rotate so the occupants feel that they have the same weight as they do on Earth?

Which transformation of energy occurs in a hydroelectric power plant? A. Potential energy to chemical energy B. Chemical energy to potential energy C. Chemical energy to Kinetic energy D. Kinetic energy to electrical energy F.