Chapter 7 (Energy)

Question 1

What are the different types of energy stores

Answer 1

-elastic potential store
-kinetic store
-internal store
-gravitational potential store
-nuclear store
-chemical potential store

Question 2

What are the ways energy can be transferred

Answer 2

-mechanically by a force acting over a distance
-temperature difference
-propagation of waves (em and mechanical sound waves)
-transferred electrically by an electric current

Question 3

How to calculate energy in the
i) kinetic store (Ek)
ii) gravitational potential store (Ep)

Answer 3

i) 1/2mv2
ii) mgh

Question 4

What is the principle of conservation of energy

Answer 4

energy cannot be created or destroyed but can be transferred from one store to another. energy in an isolated system is constant

Question 5

What is work done

Answer 5

Work done by a constant force on an object is the product of the force and the distance moved by the object in the direction of the force

Question 6

What is the formula for work done

Answer 6

Work done= Fxd

Question 7

What is power

Answer 7

Power is the work done or energy transferred per unit time

Question 8

What is the formula for power

Answer 8

P= W/t or
P= E/t

Question 9

How to calculate efficiency

Answer 9

Energy = useful energy output/total energy input x100%