Year 9 Physics Review

What name is given to the energy stored when an object is lifted above the Earth’s surface?

• chemical potential energy

• elastic potential energy

• gravitational potential energy

• kinetic energy

What is the equation used to calculate power?

• power = energy transferresd/time

• power = energy transferred × time

• power = speed × time

• power = 0.5 × energy transferred × (time)2

What is efficiency?

• useful energy transferred by a device plus the total energy supplied to the device

• useful energy transferred by a device minus the total energy supplied to the device

• useful energy transferred by a device divided by the total energy supplied to the device

• useful energy transferred by a device multiplied by the total energy supplied to the device

A football has a mass of 0.4kg and travels at a speed of 30.5m/s. What is the kinetic energy stored in the football?

• 6.1J

• 12.2J

• 186.05J

• 372.1J

A spring with a spring constant of 20N/m is extended by 0.2m. How much elastic potential energy is stored in the spring? Use the equation Ee = 1 2 k e2 .

• 0.4J

• 0.8J

• 1.6J

• 2.0J

A motor is supplied with 2000J of energy. 1850J of energy is usefully transferred. What is the percentage efficiency of the motor?

• 0.925%

• 9.25%

• 92.5%

• 925%

50 000J of water is used to heat 2kg of water. Specific heat capacity of water = 4200J/kg °C. What is the temperature change of the water? Use the equation ΔE = m c Δθ.

• 2.98°C

• 5.95°C

• 11.90°C

• 23.81°C

Which of the following is not one of the three states of matter?

• solid

• liquid

• semi-permeable plasma

• gas

What is caused by the particles in a gas colliding with the walls of a container?

• an increase in mass

• pressure on the walls of the container

• an increase in density

• a change of state

What is the equation used to calculate density?

• density = mass × volume

• density = mass/volume

• density = volume/mass

• density = mass × volume2