Starter quiz
- What is the name of the force that acts between two surfaces in contact and in the opposite direction to motion?
- drag
- friction ✓
- pull
- tension
-
- Which of these pieces of equipment can be used to measure the size of a force?
- ammeter
- thermometer
- metre ruler
- newton meter ✓
-
- Which of these units is the size of a force measured in?
- amps
- joules
- newtons ✓
- watts
-
- Which of these forces is a contact force?
- air resistance ✓
- electrostatic force
- gravitational force
- magnetic force
-
- When a book is lifted and placed on a higher shelf, it has more energy in its ______ store.
- 'gravitational' ✓
- Match each energy store to the properties that an object has when there is energy in that store.
- Energy in a chemical store ...⇔means an object may take part in a chemical reaction. ✓
- Energy in an elastic store ...⇔means an object may stretch and increase in length. ✓
- Energy in a gravitational store ...⇔means an object has mass and is at a position above Earth's surface. ✓
- Energy in a kinetic store ...⇔means an object has mass and is moving. ✓
Exit quiz
- Which two statements describe what happens to energy when it dissipates?
- The energy is used up, so there is none left.
- The energy spreads out into the surroundings. ✓
- The energy is transferred into a thermal store. ✓
- The energy is transferred into a chemical store.
-
- 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?
- A maximum amount of 160 J.
- Exactly 160 J. ✓
- A minimum amount of 160 J.
- It is impossible to tell.
-
- Match the energy values on the left to the equivalent values on the right.
- 45 000 J⇔45 kJ ✓
- 4.5 kJ⇔4500 J ✓
- 450 J⇔0.45 kJ ✓
- 0.045 kJ⇔45 J ✓
- A force of 600 N is used to lift a box above the ground. An identical box is moved three times as high by a force of 200 N. How much work was done lifting the second box compared to the first?
- 9× less
- 3× less
- the same amount ✓
- 3× more
- 9× more
-
- Put the statements in order of increasing work done on identical boxes, starting with the least work done.
- 1⇔Moving a box 3 m with a force of 5 N.
- 2⇔Moving a box 2 m with a force of 8 N.
- 3⇔Moving a box 1 m with a force of 17 N.
- 4⇔Moving a box 1.5 m with a force of 12 N.
- Aisha does 480 J of work pushing a crate 6 m along the floor. What is the size of the force that she pushed the crate with?
- 480 ÷ 6 = 80 N ✓
- 480 N
- 480 × 6 = 2,880 N
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Worksheet
Presentation
Video
Lesson Details
Key learning points
- Work done is the total amount of energy transferred.
- Work done = force × distance (moved in the direction of the force).
- Work done is measured in joules (J).
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).
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).