AQA GCSE Physics (8463), Higher tier · Forces › Forces and motion › Newton's laws of motion
Practise Newton's First Law. 12 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.
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A car travels at a steady speed along a straight, level road. The driving force on the car is 2400 N. What is the total resistive force acting on the car?
2400 N
A cyclist rides along a straight, level road. The driving force from the cyclist is 180 N and the total resistive force is 180 N. Describe the motion of the cyclist.
Moving at a constant velocity.
What is meant by inertia?
The tendency of an object to stay at rest or to keep moving with the same velocity.
Complete the sentence. An object continues to move at a constant velocity, or remain at rest, unless it is acted on by a ............
Resultant 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) Complete the sentence. If the resultant force on a stationary object is zero, the object will ............ Tick (✓) one box.[1]
start to move
remain stationary
accelerate
move at a constant speed
(b) A car travels at a steady speed along a straight, level road. The driving force on the car is 2400 N. What is the total resistive force acting on the car?[1]
(c) What happens to the velocity of a moving object if the resultant force on the object is zero?[1]
(d) Which statement is correct? Tick (✓) one box.[1]
A resultant force is needed to keep an object moving at a steady speed.
An object can only change direction if a resultant force acts on it.
A moving object always slows down when there is no resultant force.
The resultant force on an object moving at a steady speed is in the direction of motion.
Show the answer and mark scheme
(a)Answer: remain stationary
(b)Answer: 2400 N
2400 (N)
(c)Answer: It stays constant.
it stays the same / constant (the object keeps the same speed and direction)
(d)Answer: An object can only change direction if a resultant force acts on it.
Question 2Medium6 marks
A cyclist rides along a straight, level road. The driving force from the cyclist is 180 N and the total resistive force is 180 N.
(a) Describe the motion of the cyclist.[1]
(b) The cyclist pedals harder, so the driving force increases to 230 N. Calculate the resultant force on the cyclist and describe its effect on the motion.[2]
(c) The driving force stays at 230 N. After a short time the cyclist moves at a new, higher steady speed. Explain why.[3]
Show the answer and mark scheme
(a)Answer: Moving at a constant velocity.
constant / steady speed in a straight line (constant velocity)
(b)Answer: 50 N forwards; the cyclist accelerates N
50 (N) (forwards)
the cyclist accelerates / speeds up
(c)Answer: Air resistance increases with speed, reducing the resultant force until resistive force = 230 N; then the resultant force is zero and the speed is constant.
as the speed increases, the air resistance / resistive force increases
so the resultant force decreases
when the resistive force reaches 230 N the resultant force is zero, so the speed stays constant
Question 3Hard6 marks
(a) What is meant by inertia?[1]
(b) A passenger is standing, without holding on, in a bus that is moving at a steady speed. The bus brakes suddenly and the passenger falls forwards. Use Newton’s First Law to explain why.[3]
(c) Explain why a fully loaded supermarket trolley is harder to stop than an empty trolley moving at the same velocity.[2]
Show the answer and mark scheme
(a)Answer: The tendency of an object to stay at rest or to keep moving with the same velocity.
the tendency of an object to continue in its state of rest or of uniform motion (constant velocity)
(b)Answer: The bus decelerates because of a resultant force on it, but the passenger’s upper body has no resultant force on it, so it keeps moving forwards at the same velocity.
a (backward) resultant force acts on the bus, so the bus decelerates
(almost) no resultant force acts on the passenger’s upper body, so it continues to move forwards at the same velocity (inertia)
so the passenger moves forwards relative to the bus
(c)Answer: It has more mass (more inertia), so a bigger force is needed to give the same deceleration.
the loaded trolley has a greater mass, so a greater inertia / inertial mass
so a larger (resultant) force is needed to give the same deceleration / to stop it in the same time