Asample of a gas is contained in a closed rigid cylinder. according to kinetic molecular theory, what occurs when the gas inside the cylinder is
heated?
(1) the number of gas molecules increases.
(2) the number of collisions between gas molecules per unit time decreases.
(3) the average velocity of the gas molecules increases.
(4) the volume of the gas decreases.

The answer is (3) The average velocity of the gas molecules increases. In the closed rigid cylinder, the volume of the gas and number of gas molecules will not change. The number of collision will increase.

When a sample of a gas is contained in a closed rigid cylinder and the gas inside the cylinder is heated "(3) The average velocity of the gas molecules increases". The number of molecules stays the same. 

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy