Explore momentum in GCSE Physics, seeing how mass and velocity link together and how collisions, stopping distances, and car safety features all depend on changes in momentum.
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You can find more about this topic by visiting BBC Bitesize - Momentum - Higher
Only moving objects have momentum, a stationary object will have no momentum
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Abbreviated to kg m s-1 or kg m/s. Can also be expressed as newton seconds, abbreviated to N s
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Some questions will demand that you use it in this form, but to answer other questions, you may have to rearrange it, so be prepared!
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A closed system means that none of the energy within the system is lost to the environment. A closed system is often referred to as an ideal system
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p = m x v, so p = 0.5 x 1.2 = 0.6 kg m/s
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Work out the value for the total momentum before the impact. The total momentum after the impact is the same (closed system). You know the combined mass of the two trolleys when they are stuck together, so a simple rearrangement of the momentum equation will allow you to calculate the new velocity
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Straighforward use of the momentum equation. In your exam, unless the units are printed at the end of the answer space, you are expected to specify them
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Numerically, options 3 and 4 were both correct, it all comes down to units!
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At GCSE, you can assume conservation of momentum applies in collision calculations
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The missing information is the time to bring the car and the truck to a halt. Even though the truck has a greater momentum, if it is allowed more time for braking, it could be brought to a halt with a lower braking force. To stop the truck in the same time as the car would require a greater change in momentum and therefore a greater force
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