Energy Concepts

Question 1

Work done by force, for a distance “x” in the given direction of the force

Answer 1

W = Fx

Question 2

Work done by force that acts at an angle from the line of motion.

Answer 2

W = Fx cos(θ)

Question 3

Law of conservation of energy

Answer 3

Energy can not be created nor destroyed only transferred from one form to the other

Question 4

Gravitational potential energy

Answer 4

Gravitational potential energy= mass × acceleration due to gravity × difference in height
(Δ E ₚ=mg Δh)

Question 5

Elastic potential energy

Answer 5

E ₚ= 1/ 1/2 k x²

Question 6

Kinetic energy

Answer 6

Eₖ = 1/2mv²

Question 7

Work energy relationship

Answer 7

Work done one a body is equal to the change in kinetic energy of that body

Question 8

Power

Answer 8

Power = Energy transferred or work done/ time

(P=E/t)

Question 9

Dissipative Forces

Answer 9

These are forces which reduce the efficiency of a system and produce un useful forms of energy e.g. heat, sound.

Question 10

Energy efficiency

Answer 10

Efficiency = (useful energy transfer/total energy input) × 100

Question 11

Spring constant

Answer 11

F = k ΔL

(Derrived K= -F/ΔL)