1.4 Energy Concepts

Question 1

Work Done

Answer 1

The force causing a motion multiplied by the distance travelled in the direction of the motion. (Equal to the energy transferred)

Question 2

What is the unit for Work Done?

Answer 2

J, joule

Question 3

Hooke’s Law

Answer 3

The force exerted on a material is directly proportional to the extension
F = k x

Question 4

What is Electrical Potential Energy equivalent to?

Answer 4

Work Done

Question 5

Kinetic Energy (E_k) = …

Answer 5

0.5 x m x v²

Question 6

Change in Gravitational Potential (ΔE_p) = …

Answer 6

m x g x Δh

Question 7

Elastic Potential Energy (E_elastic) = …

Answer 7

0.5 x k x x²

Question 8

Conservation of Energy

Answer 8

Energy cannot be created or destroyed, only transferred from one form to another

Question 9

Work-Energy Relationship

Answer 9

fx = 1/2mv² - 1/2mu²

Question 10

Power

Answer 10

The rate of transfer of energy or the rate of work done

Question 11

What is the unit for power?

Answer 11

W, Watt or Js^-1, Joules per unit time

Question 12

P = W / …

Answer 12

t

Question 13

P = … / t (not Work done)

Answer 13

E

Question 14

P = F …

Answer 14

v

Question 15

Efficiency(%) = … / … x 100

Answer 15

Useful energy transfer
Total input energy