Hitting the Slopes

Person on a sled

In this activity, you will be asked to consider a scenario of a person sliding down a snowy hill in the winter on a sled. You will apply the principles of energy conservation to determine how this person will slide on hills of different shapes.

Sled at the top of a half-pipe

"Potential energy" is the energy an object has based solely on its position. For the snowy hill scenario, a rider at the top of the hill has more potential energy than a rider at the bottom.

Sled zooming down hill

"Kinetic energy" is the energy an object has based on its motion. In our scenario, the kinetic energy of a rider increases as his or her velocity increases.

Traced path of sled

"Conservation of energy" is a law of physics that says the total energy in a closed system will remain constant over time. Energy may change form, such as from potential energy to kinetic energy, but the total energy will not change. In our scenario, this means that a rider sliding down a hill converts potential energy to kinetic energy, and converts kinetic energy to potential energy as he or she slides up the other side, such that the total energy is always the same.

Surface of the sled meeting the snow

In reality, a rider on a sled wouldn't just slide back and forth forever; he or she would slow down and eventually come to a stop at the bottom. That's because the "system" for the rider also includes the hill. The rider loses energy by transferring it to the hill through friction.

 

About this Assignment

In this assignment, the student will:

  • Relate height of a hill to potential energy in graphical form.
     
  • Relate the transfer of potential and kinetic energy to total energy of a system.
     
  • Integrate the concept of energy transfer to the surroundings in terms of total energy of the system.