| When Sir Isaac
Newton set out the central concept of his theory - the measure of motion - he
defined the quantity of motion, or the momentum (p), as the product of the object's mass
and velocity: |
p = mv |
p = momentum (kgm/s) |
Since velocity is a vector quantity, so is momentum. If a train travels with
a velocity of 20 km/h east, and you jog along on its flatcars with a velocity of 20 km/h
west, you can run right off the end, motionless with respect to the ground. You will
drop straight down as if you had stepped off a chair in your living room. This
jogging motion can be canceled out by the opposite direction of the train. Like
velocity, linear momentum is relative. |
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