Stopping safely
I can apply an understanding of force = change in momentum ÷ time to explain how forces and momentum can be controlled.
Stopping safely
I can apply an understanding of force = change in momentum ÷ time to explain how forces and momentum can be controlled.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Increasing a stopping force decreases the time it takes a moving object to stop.
- Extending the time it takes to stop reduces the size of the stopping force.
- Many safety devices crumple on impact to increase the time that forces act before stopping a moving object.
Keywords
Stopping forces - Forces used to bring moving objects to a stop.
Stopping time - The time taken for a moving object to stop.
Momentum - The product of the mass and velocity of a moving object, p = m × v.
Crumple zones - Parts of a car designed to crumple during impacts, increasing the stopping time and reducing the stopping forces.
Airbags - These inflate rapidly in collisions and protect passengers from impacts with hard surfaces.
Common misconception
Pupils often do not understand clearly what is meant by stopping time and cannot explain why longer stopping times result in smaller forces.
Describe stopping time as the time it takes to stop ‘during which a force is acting’, and provide examples of smaller forces stopping moving objects over longer periods of time than larger forces.
To help you plan your year 11 physics lesson on: Stopping safely, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 11 physics lesson on: Stopping safely, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 physics lessons from the Forces make things change unit, dive into the full secondary physics curriculum, or learn more about lesson planning.
Content guidance
- Depiction or discussion of sensitive content
Supervision
Adult supervision recommended
Licence
Lesson video
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Starter quiz
6 Questions
displacement -
m
velocity -
m/s
mass -
kg
momentum -
kg m/s
Exit quiz
6 Questions
stopping forces -
Forces used to bring objects to a stop.
stopping time -
The time is takes for an object to stop.
momentum -
The product of mass and velocity of a moving object, $$p = m × v$$.
crumple zones -
Parts of a car designed to crumple and increase stopping time.
airbags -
Inflate in a collision and protect passengers from impacts.
seatbelts -
These stretch to increase stopping times and reduce impact forces.
crumple zones -
These collapse to increase stopping times and reduce impact forces.
air bags -
These inflate to form a protective cushion, increasing stopping times.