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Year 11
OCR
Higher

Force, mass and acceleration (a = (v – u)/t)

I can explain how to investigate the effect of force or mass on the acceleration of an object.

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New
New
Year 11
OCR
Higher

Force, mass and acceleration (a = (v – u)/t)

I can explain how to investigate the effect of force or mass on the acceleration of an object.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. Acceleration can be measured accurately using light gates or roughly measured using a stopwatch and ruler.
  2. The acceleration of an object is proportional to the resultant force acting on the object.
  3. The acceleration of an object is inversely proportional to the mass of the object.
  4. Newton's Second Law states that F = m × a.

Common misconception

It is common for pupils to fail to consider the hanging mass as part of the accelerating mass.

Emphasise that all of the moving parts in the investigation are connected, are accelerated together, and need to be included in the measurement of the mass being accelerated.

Keywords

  • Air track - A track which uses a cushion of air to reduce frictional forces in experiments.

  • Directly proportional - A relationship where one value is a constant multiple of the other, represented by y ∝ x.

  • Inversely proportional - A relationship where one value is a constant multiple of the other, represented by y ∝ 1/x.

  • Newton's Second Law of Motion - Newton's Second Law of motion states that the acceleration of an object is directly proportional to the resultant force acting on it and inversely proportional to its mass.

The investigation can be demonstrated using a crude apparatus with only approximate measurements of final speed made as an approximation to acceleration. The results can be used to convince pupils that doubling force doubles acceleration, and doubling mass halves acceleration.
Teacher tip

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

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 of the following scientists developed three laws of motion?
Albert Einstein
Galileo Galilei
Correct answer: Isaac Newton
Georg Ohm
Michael Faraday
Q2.
Which of the following forces opposes the movement of one solid object across the surface of another?
drag
gravity
upthrust
magnetism
Correct answer: friction
Q3.
Which of the following is the correct relationship between acceleration, change in velocity and time?
acceleration = change in velocity × time
acceleration = time ÷ change in velocity
Correct answer: acceleration = change in velocity ÷ time
Q4.
A sledge is pulled horizontally across flat ice with a rope. The force of the rope on the sledge is 400 N and a frictional force of 100 N opposes its motion. What is the resultant force on the sledge?
Correct Answer: 300 N, 300 newton, 300 newtons, 300N
Q5.
Which of the following is the correct unit of acceleration?
Correct answer: metres per second squared
metres per second
metre seconds
meter seconds squared
Q6.
A scooter accelerates from rest to 18 m/s in 12 s. Calculate the acceleration of the scooter.
0.67 m/s$$^2$$
Correct answer: 1.5 m/s$$^2$$
30 m/s$$^2$$
216 m/s$$^2$$

Exit quiz

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6 Questions

Q1.
Match the following key terms to their definitions.
Correct Answer:air track,A track that uses a cushion of air to reduce frictional forces.

A track that uses a cushion of air to reduce frictional forces.

Correct Answer:directly proportional,A relationship where one value is a constant multiple of the other.

A relationship where one value is a constant multiple of the other.

Correct Answer:inversely proportional,A relationship where one value halves each time the other doubles.

A relationship where one value halves each time the other doubles.

Correct Answer:Newton's Second Law of motion,Acceleration: proportional to force, inversely proportional to mass.

Acceleration: proportional to force, inversely proportional to mass.

Q2.
Which of these factors needs to be kept constant when investigating the effect of force on acceleration using an air track, glider and set of hanging masses?
the size of the force causing the acceleration
the mass placed on the hanging mass holder
the mass of the glider
Correct answer: the total mass of the system (glider and holder)
the time the glider accelerates for
Q3.
Starting with the smallest, sort the following in order of increasing resultant force.
1 - a ball of mass 1.0 kg accelerating at 3.0 m/s$$^2$$
2 - a sprinter of mass 70 kg accelerating at 3.0 m/s$$^2$$
3 - a car of mass 900 kg accelerating at 0.5 m/s$$^2$$
4 - a skydiver of mass 60 kg accelerating at 10 m/s$$^2$$
5 - an aeroplane of mass 20 000 kg accelerating at 0.10 m/s$$^2$$
Q4.
Calculate the acceleration of a dynamics trolley of mass 0.80 kg when a resultant force of 2.0 N acts on it.
0.40 m/s$$2$$
1.2 m/s$$2$$
1.6 m/s$$2$$
Correct answer: 2.5 m/s$$2$$
2.8 m/s$$2$$
Q5.
A resultant force of 2.5 kN causes a model rocket to accelerate at 5.0 m/s$$^2$$. Calculate the mass of the rocket.
0.5 kg
2.0 kg
12.5 kg
Correct answer: 500 kg
1 250 000 kg
Q6.
In an experiment, a glider of mass 0.25 kg accelerates along an air track, from rest to a velocity of 1.20 m/s in 0.50 s. What is the size of the resultant force acting on the glider?
0.15 N
0.30 N
Correct answer: 0.60 N
0.70 N
1.20 N

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