WORK, ENERGY, POWER AND MACHINES

Define power

• rate of doing work

• ability to do work

• force used to do work

• energy in doing work

What is the SI unit of work?

calculate the work done by a force of 350N when it moves a load through a distance of 2.3m

State the law of conservation of energy

• Energy is not destroyed, but changed from one form to another

• Energy can neither be created nor destroyed, but can only be changed from one form to another

• Energy in a body remains constant throughout its motion

• kinetic energy and potential energy in a body are constant

device that transforms energy is called

• transducer

• machine

• transformer

• dynamo

The following are sources of energy. list all renewable sources

• sun

• petroleum

• biogas

• coal

• hydropower

A body at 5m above the ground contains which type of energy?

Power is measured in ................. units

Calculate the average speed that a motor rated 200W raises a 40kg load

• 2m/s

• 0.5m/s

• 5m/s

• 0.2m/s

Define a machine

• device that makes work easy

• device that helps in conversion of energy

• device that is operated using electricity