2. Work is done when a force moves the point at
which it acts in the direction of the force.
Work done = force * distance
Work done = pressure * change in volume
Work done is measured in Joule, while force is
in Newton and distance is in meter. Pressure
is in Pascal and change in volume is in m3.
3.
4. Potential energy is the ability of an object to do
work as a result of its position or shape.
Elastic potential energy is the potential energy
owned by a string when it is strained.
Electric potential energy is the potential energy
stored by things with electrical charges.
Gravitational potential energy is the potential
energy of two masses when they are pulled apart.
Gravitational energy (Joule) = mass(kg)*
gravity(ms-2)*height(meter)
6. Kinetic energy is energy due to motion.
Kinetic energy(Joule)= ½ *mass(kg)*
velocity2(m2s-2)
Efficiency gives a measure of how much of
the total energy may be used and is not lost.
Efficiency = useful work done/total input
7. Hooke’s law states that, provided the elastic
limit is not exceeded, the extension of a body
is proportional to the applied.
Force (N) = constant (Nm-1) * change in
length(m)
Strain energy is the energy stored in a body
due to change of shape.
Strain energy(Joule) = ½ * constant(Nm-
1)*change in length2(m2)
8. Strain is the ratio of two lengths and does no
have a unit.
Strain = extension(m)/original length(m)
Stress is the pressure needed to cause a
certain extension to an object.
Stress(Pa) = force(N)/area parallel to the
force(m2)
Young modulus(Pa) = stress(Pa)/strain
12. The numerical value of the specific heat
capacity of a substance is the quantity of heat
energy required to raise the temperature of
unit mass of the substance by one degree.
Energy(Joule) = mass(kg)*specific heat
capacity(Jkg-1K-1)*change in temperature(C)
13. The numerical value of the thermal capacity
of a body is the quantity of heat energy
required to raise the temperature of the
whole body by one degree.
Energy(Joule) = thermal capacity(JK-
1)*change in temperature(C)
14. The numerical value of the specific latent
heat of fusion is the quantity of heat energy
required to convert unit mass of solid to
liquid without any change in temperature.
Energy(Joule) = mass(kg)*Latent energy of
fusion(Jkg-1)
15. The numerical value of the specific latent
heat of vaporization is the quantity of heat
energy required to convert unit mass of liquid
to vapor without any change in temperature.
Energy(Joule) = mass(kg)*specific latent heat
of vaporization(Jkg-1)
16. Power is the rate of doing work.
Power(Watt) = work done(Joule)/time
taken(second)
Power(Watt) = force(N)*speed(ms-1)
