7. TBQ - Potential energy near the surface of the Earth

The kinetic energy becomes zerogravitational potential energy does not changegravitational potential energy decreases continuouslyheat energy increases when an object moves with constant acceleration in the vertical directionuniform circular motionconstant velocity in the horizontal directionincreasing horizontal speed because its height increases continuouslyheight above the Earth's surface remains the samevelocity becomes zeroheight decreases continuously. Since gravitational potential energy depends only on the vertical height of the object, there is potential energy becomes maximumno change in its potential energykinetic energy remains zeropotential energy decreases rapidly during horizontal motion.

 

However, when the object is falls freely towards the groundmoves horizontally with constant speedgradually raised in the vertical directionrolls on a level surface, its height above the ground increases. As a result, its gravitational potential energy becomes zerogravitational potential energy increasesmechanical energy decreaseskinetic energy remains constant because potential energy is directly proportional to the height of the object above the Earth's surface.