3.6 Problem Solving

Conservation of Energy

Pole Vaulting

Let's consider the energy transfers used in a pole vault.

pole vault

Broken down into three main steps to reach a height that'll get you over the bar.

A. Sprint B. Plant Pole and Bend C. Spring Over Bar
pole vault pole vault pole vault

Test your knowledge by trying the problem below.

A. The first step is to build up some energy by:

A. Establishing your potential energy.
B. Building up some kinetic energy.
C. Doing work on the ground.

B. The second step is to transfer the energy to:

A. Potential energy in the pole.
B. Kinetic energy in the pole.
C. Work on the pole.

C. The last step is to transfer the energy to:

A. Kinetic energy of the pole.
B. Work on the pole.
C. Gravitational energy of the person.

Energy Strategy
A good pole vaulter -- or high jumper -- will "curl" himself or herself "around" the bar so that his or her center of mass doesn't have to go as high.   By strategically "curling their body around the pole" the athlete keeps their center of mass below the bar meaning that they can get over a higher bar with the same gravitational potential energy.