Energy

Energy

Energy is something that cannot be created or destroyed, merely transferred. The beat board is specifically designed to transfer downward and forward energy upwards. In this post, we will find out how well the beat board does its job.

Kinetic Energy

The kinetic energy is mass multiplied by velocity squared divided by 2. Knowing the mass and final velocity of the gymnast means that we can figure out her kinetic energy.

So we know that her kinetic energy at that point is about 1080J. In terms of efficiency, this is our input energy.

Potential Energy

Potential energy is the energy stored by an object by lifting it up, which will give it kinetic energy when dropped. Potential energy is mass multiplied by acceleration due to gravity times height. The video on the kinematics Page shows us the maximum height she reaches, and by knowing the mass, we can figure out the gravitational potential energy she gains. 

So we know that her potential energy is about 1046J. In our efficiency equation, this number represents energy out. 

Efficiency 

By knowing both input and output energy, we can find the efficiency. 

Therefore, the beat board is 96.9% efficient. Not bad! We can also represent this with a conservation of energy equation. 

Where does this leftover 33J go though? And energy transfer diagram will show where it may have gone. 

Some energy went to sound, a bit to kinetic energy for the board, and some went to heat energy.