Work done (W = F × s)
I can describe how energy is transferred by a force and calculate the amount.
Work done (W = F × s)
I can describe how energy is transferred by a force and calculate the amount.
Lesson details
Key learning points
- Work done is the total amount of energy transferred.
- Work done = force x distance (moved in the direction of the force).
- Work done is measured in Joule (J).
Keywords
Conservation of energy - The law of conservation of energy states that energy cannot be created or destroyed, but it can be transferred.
Dissipate - Friction can cause energy to dissipate into the surroundings by heating.
Work - Work is done whenever a force makes an object move. The amount of work is force multiplied by distance moved in the direction of the force.
Joule (J) - The unit for measuring energy is the joule (J) which is the same as the unit for measuring energy.
Kilojoule (kJ) - A thousand joules is called a kilojoule (kJ).
Common misconception
Pupils often confuse the terms force, energy, and work done and use them interchangeably.
Provide opportunities for pupils to describe events in which the three terms need to be used appropriately, e.g. in describing energy transfers for pushing (force) a crate (doing work) along a level surface (energy transferred).
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What is the name of the force that acts between of two surfaces in contact and in the opposite direction to motion?
Q2.Which of these pieces of equipment can be used to measure the size of a force?
Q3.Which of these units is the size of a force measured in?
Q4.Which of these forces is a contact force?
Q5.When a book is lifted and placed on a higher shelf, it has more energy in its store.
Q6.Match each energy store to the properties that an object has when there is energy in that store.
means an object may take part in a chemical reaction.
means an object may stretch and increase in length.
means an object has mass and is at a position above Earth's surface.
means an object has mass and is moving.
Assessment exit quiz
6 Questions
Q1.Which of these stores of energy does friction cause energy to transfer into?
Q2.Which two statements describe what happens to energy when it dissipates?
Q3.240 J of energy is transferred from a chemical store to both a gravitational store and a thermal store. If 80 J is transferred to the gravitational store, how much is transferred to the thermal store?
Q4.Match the energy values on the left to the equivalent values on the right.
45 kJ
4500 J
0.45 kJ
45 J