AQA GCSE Physics (8463), Higher tier · Forces › Forces and motion › Newton's laws of motion
Practise Newton's Second Law. 19 exam-style questions plus unlimited generated ones on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
Required practical:Acceleration (method, variables and exam tips)
Quick recall
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Write down the equation that links acceleration (a), mass (m) and resultant force (F).
F = m a
The device exerts a resultant force of 60 N on an astronaut sitting on a sliding seat. The acceleration of the astronaut and the seat is 0.80 m/s2. Calculate the total mass of the astronaut and the seat.
75 kg
A student of mass 60 kg stands on a set of bathroom scales in a lift. The scales measure the normal contact force on the student’s feet. gravitational field strength = 9.8 N/kg Name the two forces acting on the student.
Weight and the normal contact force.
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
(a) A car of mass 1200 kg accelerates at 2.5 m/s2. Calculate the resultant force on the car. Use the equation: resultant force = mass × acceleration[2]
(b) The same resultant force acts on a van with a greater mass than the car. How does the acceleration of the van compare with the acceleration of the car? Tick (✓) one box.[1]
It is smaller
It is the same
It is greater
(c) Complete the sentence. The acceleration of an object is ............ to the resultant force acting on the object. Tick (✓) one box.[1]
directly proportional
inversely proportional
equal
unrelated
Show the answer and mark scheme
(a)Answer: 3000 N
F = 1200 × 2.5
3000 (N)
(b)Answer: It is smaller
(c)Answer: directly proportional
Question 2Medium7 marks
(a) Write down the equation that links acceleration (a), mass (m) and resultant force (F).[1]
(b) A sprinter of mass 64 kg accelerates from rest to 8.0 m/s in 2.0 s. Calculate the average resultant force on the sprinter.[4]
(c) A second sprinter of the same mass experiences an average resultant force of 320 N. Calculate the average acceleration of the second sprinter.[2]
Show the answer and mark scheme
(a)Answer: F = m a
F = m a / resultant force = mass × acceleration
(b)Answer: 256 N
a = 8.0 ÷ 2.0
a = 4.0 (m/s2)
F = 64 × 4.0
256 (N)
(c)Answer: 5.0 m/s2
a = 320 ÷ 64
5.0 (m/s2)
Question 3Hard6 marks
Astronauts in orbit cannot measure their mass using bathroom scales. Instead, a device pushes the astronaut with a known force and measures the astronaut’s acceleration.
(a) Explain what is meant by inertial mass.[2]
(b) The device exerts a resultant force of 60 N on an astronaut sitting on a sliding seat. The acceleration of the astronaut and the seat is 0.80 m/s2. Calculate the total mass of the astronaut and the seat.[2]
(c) The mass of the sliding seat is 5.0 kg. What is the mass of the astronaut?[1]
(d) Explain why this method gives the same value for the astronaut’s mass as it would on the Earth.[1]
Show the answer and mark scheme
(a)Answer: It measures how difficult it is to change an object’s velocity; inertial mass = force ÷ acceleration.
a measure of how difficult it is to change the velocity of an object
(defined as) force ÷ acceleration
(b)Answer: 75 kg
m = 60 ÷ 0.80
75 (kg)
(c)Answer: 70 kg
70 (kg)
(d)Answer: Inertial mass does not depend on gravitational field strength.
inertial mass (force ÷ acceleration) does not depend on the gravitational field strength / on weight