Starter quiz
- Which international standard unit is used to measure speed and velocity in physics? Give the symbols.
- 'm/s' ✓
- A roller-skater covers a distance of 520 m in 40 s. Calculate his speed.
- 0.08 m/s
- 2.6 m/s
- 13 m/s ✓
- 480 m/s
- 20 800 m/s
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- Which of these is a vector quantity?
- distance
- mass
- speed
- velocity ✓
- volume
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- A lorry is travelling along a straight road. Its speed increases from 5.6 m/s to 8.4 m/s. What is the change in velocity for the lorry?
- 8.4 m/s
- 5.6 m/s
- 2.8 m/s ✓
- 0 m/s
- -2.8 m/s
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- How far will a wind-up toy travel if it has a speed of 0.02 m/s and it moves for 1 minute?
- '1.2 m' ✓
- How long will it take a rocket traveling at 5.0 km/s to travel a distance of 500 m?
- 25 s
- 10 s
- 1.0 s
- 0.25 s
- 0.1 s ✓
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Exit quiz
- Match the key words and phrases to their explanations.
- velocity⇔how fast something is moving in a particular direction ✓
- rate of change⇔how much a quantity changes each second ✓
- acceleration⇔the rate of change of velocity ✓
- deceleration⇔a change in velocity where the object is slowing down ✓
- delta v (𝚫)⇔a symbol used to represent change in velocity ✓
- Match the quantities to the unit definitions.
- velocity⇔a vector measured in m/s ✓
- distance⇔a scalar measured in m ✓
- acceleration⇔a vector measured in m/s ✓
- speed⇔a scalar measured in m/s ✓
- displacement⇔a vector measured in m ✓
- Which of these equations correctly give acceleration ()?
- acceleration = change in velocity + time
- acceleration = change in velocity ÷ time ✓
- acceleration = change in velocity × time
- ✓
-
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- A car takes 17.6 s to accelerate from 0 m/s to 44 m/s. Calculate the acceleration of the car in m/s. You do not need to enter the unit.
- '2.5' ✓
- A motorcycle reduces its velocity from 25 m/s to 14 m/s in 5.5 s. What is the size of the deceleration?
- -2.0 m/s ✓
- -7.1 m/s
- -11 m/s
- -44.5 m/s
- -49.5 m/s
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- An arrow is travelling at 20 m/s. It hits a target and slows to 2.0 m/s in a time of 0.2 s. Calculate the acceleration during the impact with the target. You do not need to enter the unit.
- '-90' ✓
Worksheet
Presentation
Video
Lesson Details
Key learning points
- Acceleration is equal to the amount that velocity changes in one second.
- Acceleration is the rate of change of velocity.
- Average acceleration = change of velocity / time (a = Δv/t)
- An object that is slowing down is decelerating.
- An object that is decelerating has a negative acceleration.
Common misconception
Pupils often think that if velocity or speed is increasing, then acceleration must also be increasing. Pupils often don't associate a change in direction at a constant speed with an acceleration.
Before teaching acceleration, consolidate an understanding of the differences between velocity and changes in velocity. Discuss how an object can be accelerating AND travelling at a constant speed (circular motion).
Keywords
Acceleration - The acceleration of an object is the rate of change of velocity. This is how much the velocity changes per second.
Deceleration - Deceleration is used to describe a change in velocity where the object slows down.
Velocity - The velocity of an object is the speed in a particular direction. This is the rate of change of displacement.
Delta v (δv) - The change in velocity is represented by 𝚫v.
Rate of change - A rate of change is how much a quantity is changing by every second.