Energy Concept

Calculate kinetic energy of an elephant of mass 2000 kg travelling at 5 m/s.

• 15 kJ

• 20 kJ

• 25 kJ

• 30 kJ

Kinetic energy will be double if the _______ is double.

• mass

• velocity

• distance

• acceleration

What is the potential energy of a 12 kg mass raised to a height of 25 m?

• 1 kJ

• 2 kJ

• 3 kJ

• 5 kJ

Jack put on his bag-pack of weight 100N. He then started to climb up a ladder up a height of 20 m. How much work was done?

• 0.5 kJ

• 1 kJ

• 1.5 kJ

• 2 kJ

When doing a chin-up, a physics student lifts her 42.0-kg body a distance of 0.25 meters in 2 seconds. What is the power delivered by the student's biceps?

• 40 Watts

• 45 Watts

• 52.5 Watts

• 55 Watts

The following regarding law of conservation of energy EXCEPT

• Energy cannot be destroyed

• Energy can be created

• Energy can be transform into one form into another

• Total amount of energy in the process is constant

The SI unit of temperature is

• Kelvin

• Celcius

• Farenheit

Electromagnetic waves transfer heat by means of

• conduction

• convection

• radiation

Conduction is the main heat transfer in

• solid

• gases

• liquid

• vacuum

The following are the main ways to prevent overheating of the ball bearing in rotating anode EXCEPT

• small cross sectional area

• stem made from poor conductivity

• stem made as short as possible

• blackened the anode rotor