Work, Energy and Power

Question 1

Law of Constervation of Energy

Answer 1

Energy can be neither created nor destroyed but it can be transformed from one form to another

Question 2

Energy Formulas

Answer 2

GPE: mgh

Kinetic Energy: 1/2 X mv^2

Question 3

Work done

Answer 3

Work done is the change in energy
it is a scalar quantity and is dependant on the path followed
work done= force X displacement
Unit: Joules(J)
When force is applied in the same direction as the displacement, the work done is positive
When force is applied in the opposite direction as the displacement, the work done is negative
When force applied is perpendicular to the displacement, the work done is zero

Question 4

Power

Answer 4

It is the rate of work done
Power= Work Done/ Time
Unit: Joules/ Second (J/s) OR Watts(W)

Question 5

Efficiency

Answer 5

Efficiency= (useful output/ total input) * 100