Work and Energy | 4

Question 1

Work done formula

Answer 1

Force X Distance Moved

Newton meter / Joules

Question 2

% Energy Efficiency formula

Answer 2

Useful Energy
————————– X 100
Total Input energy

Question 3

GPE formula

Answer 3

mgh

Question 4

KE formula

Answer 4

1/2m x v2

Question 5

Power formula

Answer 5

Work Done / Time

Energy Transformed / Time

Force x Speed

Question 6

Energy

Answer 6

Capacity of a object to do work

Joules

Question 7

Law of conservation of energy

Answer 7

Energy cannot be made or destroyed , only changed from one form to another

Question 8

GPE

Answer 8

Energy possessed by a object when it is raised at a height above surface

Depends on mass of object / height above ground

Question 9

KE

Answer 9

Energy possessed by a object in motion

Depends on :

velocity of object
mass of object

Question 10

Explain the conversion of GPE to KE as a object falls down

Answer 10

As it falls down its energy possessed stays the same , but transforms into KE proportionally

When it is half way down , 1/2 energy is in KE and 1/2 in GPE

When it hits the ground all GPE is dissipated and energy changes into heat and sound aswell

Question 11

Power

Answer 11

Amount of work done over time / Rate of work done

Watts

1 Watt = 1 J/s

40 W bulb does 40J of work per second