Edexcel IGCSE Physics 4.3 Conservation of energy
Practise applying conservation of energy to explain lost energy, changing stores and why proposed devices cannot create extra output.
- Syllabus
- First assessment 2019
- Course
- Physics 4PH1
Exam points
- challenge claims that energy is destroyed by naming the store or surroundings it is transferred to
- use conservation to link decreasing kinetic or GPE stores to thermal stores and work done by friction
- calculate wasted energy by subtracting useful output from the total energy transferred
4.3 Conservation of energy question 1
The photograph shows a toy car. When the toy car is pulled backwards, energy is stored in the elastic store as the rubber band is twisted.
When the car is released, some of the energy from the elastic store is transferred to the kinetic store of the car.
The remaining energy is transferred into the thermal store of the surroundings.
Question (a)
(a)
State what is meant by the principle of conservation of energy.
[ 1 ]
Question (b)
(b)
The car is pulled backwards so that there is 165 J of energy in its elastic store.
When the car is released, this energy is transferred to the car's kinetic energy store with an efficiency of 15\%.
[ 4 ]
Question (i)
(i)
Calculate the energy transferred into the thermal store of the surroundings.
energy transferred to thermal store = ............ J
[ 4 ]
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