Changing momentum
I can use the equation force = mass × change in velocity ÷ change in time to calculate the size of force involved in changing momentum in a certain amount of time.
Changing momentum
I can use the equation force = mass × change in velocity ÷ change in time to calculate the size of force involved in changing momentum in a certain amount of time.
Lesson details
Key learning points
- The momentum of an object is changed by a resultant force acting over a period of time.
- Force = rate of change of momentum, F=Δp/t = mv – mu/t
- The size of an impact force can be changed when the duration of the impact changes.
Common misconception
Pupils often confuse the terms force and momentum.
Make explicit the understanding that forces change the motion of an object, and that the motion of an object (that a force can change) can be described by its momentum.
Keywords
Momentum - is the product of the mass and velocity of an object, p = m v, it is a vector quantity
Initial velocity, u - is the velocity of an object at the start of a phase of motion, represented by u
Final velocity, v - is the velocity of an object at the end of a phase of motion, represented by v
Rate of change of momentum - is the change in momentum per second, this is equal to the resultant force acting on an object
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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Starter quiz
6 Questions
Exit quiz
6 Questions
momentum -
the product of the mass and velocity of an object, $$p = m × v$$
initial velocity -
the velocity of an object at the start of a phase of motion, $$u$$
final velocity -
the velocity of an object at the end of a phase of motion, $$v$$
rate of change of momentum -
the change in momentum per second, equal to the resultant force