Work and power
● Work is the transfer of energy through motion
● Amount of force depends on 2 things
○ The amount of force exerted
○ The distance over which the force is applied
● If you push a box with force 1 newton for a distance of 1 meter, you have done 1 joule of work
● Work → Force x Distance
(joules) (Newton) (metre)
● Work(force at angle to distance)
○ Force x Distance x Cos
●
Work done against gravity
○ Mass x gravity x height (mgh)
● Power
○ The rate at which work is done
○ The rate at which energy is expanded or absorbed
● Power = Energy transferred/time
● Power = Change in work/time
● 1 horsepower → 746 watts
● 1 watt → 1 joule per second
● Efficiency
○ Efficiency → useful Energy output/Energy input x 100
○ Efficiency → useful Power output/Power input x 100
