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Year 10
OCR
Higher

Calculating acceleration (a=(v-u)/t)

I can calculate the acceleration and deceleration of objects.

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New
New
Year 10
OCR
Higher

Calculating acceleration (a=(v-u)/t)

I can calculate the acceleration and deceleration of objects.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. Acceleration is equal to the amount that velocity changes in one second.
  2. Acceleration is the rate of change of velocity.
  3. Average acceleration = change of velocity/time [a = (v-u)/t]
  4. An object that is slowing down is decelerating.
  5. 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.

  • Rate of change - A rate of change is how much a quantity is changing by every second.

Be careful when describing directions as acceleration and velocity are often in opposite directions. State what you are describing the direction of, for example 'The car is moving to the left, the positive direction, but it is slowing down meaning that the acceleration is to the right, negative'.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
Which international standard unit is used to measure speed and velocity in physics? Give the symbol.
Correct Answer: m/s, metre per second, metre/s, metre/second
Q2.
Which of these is a vector quantity?
speed
mass
Correct answer: velocity
volume
Q3.
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?
1.4 m/s
Correct answer: 2.8 m/s
5.6 m/s
8.4 m/s
14 m/s
Q4.
A roller-skater covers a distance of 520 m in 40 s. Calculate their speed.
0.8 m/s
Correct answer: 13 m/s
26 m/s
480 m/s
20 000 m/s
Q5.
How far will a wind-up toy travel if it has a speed of 0.2 m/s and it moves for 1 minute? Give the correct unit.
Correct Answer: 1.2 m, 120 cm, 1.2 metre, 1.2 metres, 120 centimetres
Q6.
How long will it take a rocket traveling at 5.0 km/s to travel a distance of 500 m?
Correct answer: 0.1 s
0.25 s
1.0 s
10 s
25 s

Exit quiz

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6 Questions

Q1.
Match the key words and phrases to their explanations.
Correct Answer:velocity,how fast something is moving in a particular direction

how fast something is moving in a particular direction

Correct Answer:rate of change,how much a quantity changes each second

how much a quantity changes each second

Correct Answer:acceleration,the rate of change of velocity

the rate of change of velocity

Correct Answer:deceleration,the rate of change of velocity

the rate of change of velocity

Q2.
Match the quantities to the unit definitions.
Correct Answer:velocity,a vector measured in m/s

a vector measured in m/s

Correct Answer:distance,a scalar measured in m

a scalar measured in m

Correct Answer:acceleration,a vector measured in m/s$$^2$$

a vector measured in m/s$$^2$$

Correct Answer:speed,a scalar measured in m/s

a scalar measured in m/s

Correct Answer:displacement,a vector measured in m

a vector measured in m

Q3.
Which of these equations correctly give acceleration ($$a$$)?
acceleration = change in velocity + time
Correct answer: acceleration = change in velocity ÷ time
acceleration = change in velocity × time
Correct answer: $$a = {(v-u) \over t} $$
$$a = {(v-u) \times t} $$
Q4.
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$$^2$$. You do not need to enter the unit.
Correct Answer: 2.5, 2.5 m/s^2, 2.5 m/s2
Q5.
A motorcycle reduces its velocity from 25 m/s to 14 m/s in 5.5 s. Calculate the deceleration.
Correct answer: -2.0 m/s$$^2$$
-7.1 m/s$$^2$$
-11.0 m/s$$^2$$
-44.5 m/s$$^2$$
-49.5 m/s$$^2$$
Q6.
A cricket ball moving at 20 m/s is hit by a bat, and then travels in the opposite direction at 15 m/s. The impact lasts for 0.05 s. Calculate the acceleration. You do not need to enter the unit.
Correct Answer: -700, 700, -700 m/s^2, 700 m/s^2