What is the definition of speed and the formula for calculation?

Is it possible to use the energy from two atoms colliding to create a clean burning lasting fuel source with a large amount of force? is it also possible to harness that energy from the two atoms colliding to create a clean energy source that will last for years from just two atoms colliding. is there a possibility to control and store that energy for years but slowly let the energy out enough to power cities cheaper and faster.

0.5 kg of silver increases temperature from 0 celsius to 7 celsius when heat is added how much heat energy produced this change in temperature

If an object is thrown in an upward direction from the top of a building 1.6 x 102 ft. high at an initial velocity of 21.82 mi/h, what is its final velocity when it hits the ground?