1.8 Work, Potential and Kinetic Energy

Question 1

Energy

Answer 1

ability to do work

Question 2

work done

Answer 2

work done by constant force is the product of the force and the distance moved in the direction of the force

Question 3

work done equation

Answer 3

W = Fs

Question 4

how can you work out work done from force-displacement graph

Answer 4

area under the graph

Question 5

potential energy on Earth’s surface at ground level

Answer 5

0

Question 6

potential energy

Answer 6

energy stored in a mass due to its position in a gravitational field

Question 7

gravitational potential energy equation

Answer 7

Ep = mgh

Question 8

kinetic energy

Answer 8

energy an object has due to its motion (or velocity)

Question 9

kinetic energy equation

Answer 9

Ek = 1/2mv2

Question 10

power

Answer 10

rate of doing work

Question 11

power equation

Answer 11

P = WD/t
P = Fv

Question 12

Conservation of energy

Answer 12

energy cannot be created or destroyed but can be changed from one form to another

Question 13

efficiency

Answer 13

ratio of the useful energy output from the system to the total energy input

Question 14

efficiency equation

Answer 14

useful power out/total power in
useful energy out/useful energy in

Question 15

unit for efficiency

Answer 15

none as dimensionless
expressed in ratio or % format

Question 16

ways to improve energy efficiency in your everyday life

Answer 16

insulating roof - 1/3 heat lost via roof
taking shower instead of bath - uses 1/2 the energy
turn down heating - 1oC reduces consumption by 5%
turn off unused appliances - stand by mode still uses power
uses energy efficient appliances - swap filament bulbs for LEDs
wash clothes economically - low temperature washes, full loads, line drying