Force and Momentum

On an aircraft the opposing pair of forces that are trying to speed up and slow down the aircraft are the thrust and drag. The opposing pair of forces that are trying to pull the aircraft up and down are the lift and the weight.

If the forces on an object are unbalanced, and it is free to move, it will accelerate (or decelerate).

Momentum is calculated by multiplying mass and velocity. We can calculate the change in momentum by multiplying the force on the object by the time that the force acts. A large force is needed to produce a sudden change in momentum.

Newton's second law of motion states that force = mass x acceleration (f=ma).

Word Equations
Momentum (Kg.m.s^-1) = Mass (Kg) x Velocity (m.s^-1)
Impulse (Change in Momentum) = Force (N) x Time (s) *
(* provided that the force and mass don't change)
Force (N) = Mass (Kg) x Acceleration (m.s^-2)