January Week 4 Secondary Two Energy Revision

What is the concept demonstrated in this video?

• charpy impact test (the minimum amount of energy required to destroy an

  object)

• conservation of energy

• destroying objects using a wrecking ball

• Newton’s three laws of motion

What are the types of energy conversion shown in this video?

• gravitational potential energy → kinetic energy

• gravitational potential energy → kinetic energy + sound energy

• gravitational potential energy → kinetic energy + heat energy

• gravitational potential energy → kinetic energy + heat energy + sound energy

A pendulum is shown in the diagram below. At which position does the pendulum have maximum kinetic energy? Assume there is no energy loss to the surroundings.

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• The kinetic energy is the same at all positions.

A pendulum is shown in the diagram below. At which point does the pendulum have the greatest amount of combined kinetic and gravitational potential energy? Assume there is no energy loss to the surroundings.

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• The combined kinetic and gravitational potential energy is the same at all positions.

“If a wrecking ball is released from a height of 2 m, it cannot reach a height higher than 2 m.”

What are the conditions required for the above statement to be true?

• The object must be released with a small push.

• The object must be released from a minimum height of 1 m.

• The object must be released from rest (at zero speed).

• The object must be smaller than 2kg.