Gravity if you are coasting.
Gravity pulls it down and the weight of a car is less dense than a hill and therefore it goes down
The skier going up the hill gains potential energy due to its height increase, which is stored energy that can be released when the skier goes back down the hill. As the skier goes down the hill, the potential energy is converted into kinetic energy, which is the energy of motion.
a hill is a steep road that has either grass or something else and goes both up and down
My ball rolled down the hill.
a penguin rolling down a hill
It goes down hill from left to right.
Light
gravity is the one to blame . gravity pulls down the biker closer to earth so it goes faster going down and slower going down
a wheel barrow
potential energy
If you are driving a loaded tractor trailer, you would downshift to gain more power when going up hill and downshift to control speed when going down hill.
Man The young go up the hill walking on two legs, The old come down the hill using a cane.