Equations

Question 1

Equation for work done with units.

Answer 1

Work done (joules) = force applied(newtons)* distance along the line of action of the force (meter),

Question 2

How to calculate change in object’s gravitation potential energy store (with units).

Answer 2

Change in object’s gpe store (joules) = weight(newtons)* change of height (metres)

Question 3

How do you calculate change of gravitational potential energy store?

Answer 3

Change of gravitational potential energy stone
= mass(kg)* gravitational field strength(n/kg) * change in height.

Question 4

How to calculate kinetic energy?

Answer 4

Kinetic energy (joules) =
0.5* mass(kg) *speed^2(m/s)

Question 5

Calculate elastic potential energy

Answer 5

Elastic potential energy (joules)
= 0.5 x spring constant (newtons/metre) *extension^2 (metres)

Question 6

How do you calculate power?

Answer 6

Power(watts)=
Energy transferred to appliance (joules) /. Time take of energy to be transferred (seconds)

Question 7

How do you calculate the efficiency of an appliance in terms of power?

Answer 7

Efficiency =
(useful power out / total power in ) x100

Question 8

How do you calculate power wasted by an appliance

Answer 8

Power wasted by an appliance =
Total power input - useful power output