Energy and Energy transfromation

Energy is ................. .

• a motion

• a type of force

• the ability to do work

• nothing

A car's engine transfers chemical energy into kinetic, heat and sound energies. Which energy is useful energy in this situation?

• kinetic energy

• heat (thermal energy)

• sound energy

• none of them

What is the formula to calculate the efficiency?

• $\%\ efficiency=\frac{useful\ energy\ output}{total\ energy\ input}\times100\ \%$

• $\%\ efficiency=\frac{waste\ energy}{total\ energy\ input}\times100\ \%$

• $\%\ efficiency=\frac{useful\ energy\ output}{waste\ energy}\times100\ \%$

• $\%\ efficiency=\frac{waste\ energy}{useful\ energy\ output}\times100\ \%$

Kinetic energy relates to .......... .

• the height of object

• the motion

• the temperature of medium

• the atmospheric pressure

Which formula is used to calculate the kinetic energy (KE)?

• $KE\ =\ mgh$

• $KE\ =\ \frac{1}{2}mgh$

• $KE\ =\ \frac{1}{2}mv^2$

• $KE\ =\ mv^2$

What is the kinetic energy of an F1 car with a mass of 500 kg and speed of it is 40 m/s.

• 10 000 J

• 20 000 J

• 40 000 J

• 400 000 J

Which formula is used to calculate the gravitatinal potential energy (GPE or PE)?

•  $GPE\ =\ mgh$ 

•  $GPE\ =\ \frac{1}{2}mgh$ 

•  $GPE\ =\ \frac{1}{2}mv^2$ 

•  $GPE\ =\ mv^2$ 

A skier has a mass of 70 kg and travels up in a ski lift at a vertical height of 300 m. Calculate the change in the skier’s gravitational potential energy. Know that g = 9.81 m/s²

• 103 005 J

• 206 010 J

• 21 000 J

• 2943 J

When a battery powered LED torch is switched on, which is the useful energy change within the LED?

• Electrical energy to thermal energy

• Chemical energy to light energy

• Chemical energy to electrical energy

• Electrical energy to light energy