Chapter 4 Work and Machines Sect 1 - What is Work?

false

Because a watt is a relatively small unit of power, power is often measured in larger units called Kilowatts (kW) which equals 100 watts.

Power = Work / Time

Power is calculated by dividing the amount of work done by the amount of time it takes to do the work.

Power = Force x Distance / Time

Since work is equal to force times distance, you can rewrite the equation for power as this.

joule

The SI unit of work is the newton x meter (N*m). This unit is also called a _____ in honor of James Prescott Joule, a physicist who studied work in the mid-1800s.

Work = Force x Distance

The amount of work done on an object can be determined by multiplying force times distance.

work

This is done on an object when the object moves in the same direction in which the force is exerted.

true

To do work on an object, the object must move some distance as a result of your force. If the object does not move, no work is done, no matter how much force is exerted.

horsepower

When people talk about power for vehicles, they use this power unit instead of the watt. One of these is equal to 746 watts. This unit of power is not a SI unit.

power

is the rate at which work is done. Power equals the amount of work done on an object in a unit of time.

joule per second

the SI unit of power when work is measured in joules and time in seconds. This unit is also known as a Watt (W), in honor of James Watt who made great improvements to the steam engine.