Momentum Introduction
MOMENTUM is defined as the MASS of an object multiplied by its VELOCITY.
The symbol for MOMENTUM is p.
formula: p = mv
So the units are kg.m.s-1
Momentum is a vector quantity, which means it needs a magnitude AND a direction in the answer.
Momentum is also referred to as "quantity of motion".
Here are a few examples to get going!
Question 1
A trolley has a mass of 4kg, and a velocity of 2m.s-1 rightwards.
- 1.1 Write done the formula to calculate its momentum.
- p = mv
- 1.2 Calculate the momentum.
- p = mv
p= (4)(2)
p = 8kg.m.s-1 rightwards
Question 2
A trolley has a mass of 8kg, and a momentum of 24kg.m.s-1 rightwards.
- 2.1 What is the symbol for momentum?
- p
- 2.2 Define velocity.
- rate of change of displacement
- 2.3 Calculate the velocity
- p = mv
24 = 8v
v = 3 m.s-1 rightwards
So it is easy to calculate the momentum of an object. But what do we learn from this?
As an example, a 2kg trolley moving at 10m.s-1 will have the same momentum as a 5kg trolley that is moving slower at 4m.s-1.
Both have a momentum of 20kg.m.s-1.
This is an important thing to know!
For now, just be able to apply the p = mv formula, and calculate stuff!