- Momentum is defined as the product of mass and velocity.
- Momentum is a vector quantity. It has both magnitude and direction.
- The SI unit of momentum is kgms-1
A student releases a ball with a mass of 2 kg from a height of 5 m from the ground. What would be the momentum of the ball just before it hits the ground?
In order to find the momentum, we need to know the mass and the velocity of the ball right before it hits the ground.
It’s given that the mass, m = 2kg.
The velocity is not given directly. However, we can determine the velocity, v, by using the linear equation of uniform acceleration.
This is a free falling motion,
The initial velocity, u = 0
The acceleration, a = gravirational acceleration, g = 10ms-2
The dispacement, s = high = 50m.
The final velocity = ?
From the equation
v2 = u2 + 2as
v2 = (0)2 + 2(10)(5)
v = 10ms-1
p = mv =(2)(10) = 20 kgms-1