Chapter 7 Energy and Power :)

Why a car with the same velocity as a motorcycle have higher kinetic energy?

• Car has larger size

• Car is capable of carrying more load

• Car has more tires

• Car has larger mass

Which of the following statement describes the principle of conservation of energy?

• Energy cannot be created and destroyed but can change to other form

• Some of the energy is destroyed when it change form

• Energy can be created but cannot be destroyed

• Energy can be created and destroyed

Work is defined as the product of _____ (mass/force) and displacement.

S.I unit for work is ____ (Joule/Newton).

Diagram 3 shows a coconut falling from a tree. What is the speed of the coconut before it reaches the ground?

Diagram 1 shows two situation, P and Q. What type of energy is possessed by situation P and Q?

• P : Gravitational Potential Energy

  Q : Elastic Potential Energy

• P : Gravitational Potential Energy

  Q : Kinetic Energy

• P : Elastic Potential Energy

  Q : Kinetic Energy

• P : Kinetic Energy

  Q : Gravitational Potential Energy

A crane uses 112.5W to lift iron rod weighing 900N for height of 4.5m. How much time does the crane take to complete the work?

• 3.3 minutes

• 33 seconds

• 3.6 minutes

• 36 seconds

Which of the following activity uses the highest energy?

• Pushing a punctured bicycle

• Finishing homework

• Disposing trash

• Climbing mountain with a bag containing necessities for two days

Diagram 2 shows Hakim is playing skateboard. At which position, the gravitational potential energy is zero while the kinetic energy is maximum?

• P

• Q

• R

• S

____ (Power/Work) is defined as the product of force and displacement in the direction of the force.