What is power?

What is power?

Not like superpowers!

Multiple Select

What TWO things do you need to calculate WORK?

• Force

• Speed

• Distance

• Mass

What is power?

Have you heard of the term horsepower before?

It's often used to describe cars and trucks.

But what is it actually?

Power and Work

• When a car's engine moves it, it does work on the car.

• A more powerful engine can do more work, or do the same amount of work faster.

• But what IS power?

Power!

• Power is the amount of work done per unit of time.

• Just like velocity, power is what we call a rate!

Multiple Select

What two other measures are involved in power?

• Work

• Force

• Time

• Mass

Measuring Power

• power = work ÷ time

• Remember, work = force ÷ distance, so you can all write:

• P = (F * d) ÷ t

Watt's Up?

The SI unit for power is the watt (W), named for James Watt.

1 W = 1 J every second

Multiple Choice

If you have a 60 W bulb, how much energy does it put out every second?

• Not enough information

• 60 J

• 120 J

So, horsepower?

James Watt built the first practical steam engine.

To have something to compare to, he measured how much power a horse could put out: horsepower.

Multiple Choice

The rate at which work is done is:

• energy

• power

• velocity

Multiple Choice

Power = (force * ______) ÷ time

• distance

• velocity

• weight

Multiple Choice

One watt equals one...

• joule per second

• joule times seconds

• joule

Poll

How well do you think you understand today's concept?

• Really well!

• Okay.

• Not at all...

Any questions?