Answer:
On a roller coaster, energy changes from potential to kinetic energy and back again many times over the course of a ride. Kinetic energy is energy that an object has as a result of its motion. Traditionally, the coaster cars are pulled up the first hill by a chain; as the cars climb, they gain potential energy.
'Frequency' is a word that often confuses some people ... for no good reason.
It just means "frequent-ness" or "often-ness" ... how often something happens.
The SI unit of frequency is the Hertz (Hz). Hz means 'per second'.
So " 13 Hz " means 13 per second.
Here are examples of frequency:
-- 780 kilohertz (on your AM radio dial)
-- 98.7 Megahertz (on your FM dial)
-- 5.8 Gigahertz
-- twice a day
-- three per week
-- every 6 months
When balanced forces act on an object at rest, the object will not move. If you push against a wall, the wall pushes back with an equal but opposite force. Neither you nor the wall will move. Forces that cause a change in the motion of an object are unbalanced forces.
