Momentum is defined as the product of mass and velocity.
momentum = mass x velocity
The units of momentum are kilogram metres per second - kg m/s
As the velocity or mass increases, so does the momentum.
Newton's laws of motion
1. An object will continue to stay at rest or at a steady speed unless a resultant force acts upon it.
2. When an unbalanced force acts on an object it accelerates.
3. Every action has an equal and opposite reaction.
Terms you need to know
mu = initial momentum
mv = final momentum
mv - mu / m(v - u) = change in momentum
∆ = the greek letter delta, representing 'change in'
Rate of change of momentum
Force (in N) = change in momentum (in kg m/s) / time (in seconds)
Examples
A tennis ball (0.3 kg) hits a raquet at 3 m/s and rebounds in the opposite direction at 6 m/s. What impulse is given to the ball?
∆P (change in momentum) = m ( v - u)
= 0.3 ( -6 -3 )
= 2.7 kg m/s
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