Calculating the energy of moving objects (KE=1/2mv2)
Lesson details
Learning outcome
I can calculate the energy an object has because it is moving.
Key learning points
- Energy is measured in joules (J).
- Doubling the mass of a moving object doubles the energy it has in its kinetic store.
- Doubling the speed of an object increases the energy it has in its kinetic store by four times.
- The energy an object has in its kinetic store of energy is found using the equation KE = ½ mv².
Keywords
Work done - Work is done whenever a force makes an object move. The amount of work done is equal to the force multiplied by distance moved in the direction of the force.
Kinetic store - If an object is moving and has a mass, then there is energy in its kinetic store.
Directly proportional to - If two quantities are directly proportional, then as one increases, the other also increases at the same rate.
Kinetic energy - The energy an object has in its kinetic store is referred to as the object’s kinetic energy.
Common misconception
When calculating energy in the kinetic store, pupils often work out ½ mv and then square everything, rather than just the speed.
Scaffold calculations to show how kinetic energy is calculated, taking pupils through how to do this on their calculators without making a mistake.
Teacher tip
Do some quick calculations on calculators with pupils using mini–whiteboards to show their answers, in order to quickly identify those not squaring speed correctly on their calculators.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which properties of an object can be increased so it has more energy in its kinetic store?
Q2.Why does a shopping trolley that has been pushed and then let go of come to a stop?
Q3.What happens to the amount of work done moving a car, if the car is pushed with the same size force for three times the distance?
Q4.In which of these situations does the applied force not do any work?
Q5.How would you calculate the work done by a catapult in shooting a small ball forward?
Q6.A catapult does work on a small ball to fire it vertically up into the air. What is the amount of work done on the ball equal to?
Assessment exit quiz
6 Questions
Q1.How much energy will be transferred to the kinetic store if three times the amount of work is done on kicking a football?
Q2.If friction and air resistance are ignored, how much energy is dissipated by a toy car moving across a table?
Q3.What happens to the amount of energy in the kinetic store of a ball if it is moving at two times the speed?
Q4.What is kinetic energy?
Q5.What is the kinetic energy of a discus of mass 2 kg moving at a speed of 8 m/s?
Q6.What is the mass of a javelin that has a kinetic energy of 72 J and a speed of 12 m/s?
To help you plan your 10 physics lesson on: Calculating the energy of moving objects (KE=1/2mv2), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 physics lesson on: Calculating the energy of moving objects (KE=1/2mv2), 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 Energy of moving objects unit, dive into the full secondary physics curriculum, or learn more about lesson planning.