Albert Teen YOU ARE LEARNING:  Understanding Power  # Understanding Power ### Understanding Power

We will learn the meaning of the term Power in terms of energy, transfer and rate.

Two cars are identical in every way, except for the fact that car 1 has a more powerful engine. Which of the two cars will be quicker to finish a 1 mile straight race? Two cars are identical in every way, except for the fact that car 1 has a more powerful engine. Which of the two cars will transfer the more energy during a 1 mile straight race? Power is defined as the rate of energy transferred. It is measured in watts.

If car 1 has a more powerful engine than car 2, car 1 will transfer more chemical energy in the petrol to kinetic energy which allows the car to move faster.

If somebody drops a ball from the top of the stairs to the bottom of the stairs, which energy store changed due to a change in height? As a ball is dropped from the top of a flight of stairs to the bottom, what is the gravitational potential energy changed into? As the ball moves down the stairs, the gravitational potential energy is changed into kinetic energy. The work done is the equivalent to this energy transfer.

In order to calculate power, **** we need to know a few things. We need to know the energy transfer. What else? Power is the rate of energy transferred in a system. So in order to calculate power, we need to know the energy transfer and the time it took to transfer that energy.

Remember that power is calculated in watts (W).

What is the energy transfer as a person walks up the stairs? If we know the time it took for a person to walk up the stairs, are we able to calculate the power, if we also have the energy transfer values? 