Define momentum as mass × velocity; recall and use the equation p = m v

1.6 Momentum

Objective

Define momentum as the product of mass and velocity, and recall the equation p = m v.

Key Concepts

• Momentum is a vector quantity.
• It depends on both the magnitude and direction of velocity.
• Units: kg·m s⁻¹ (kilogram metres per second).

Equation

The magnitude of linear momentum is given by

\$p = m v\$

where p is momentum, m is mass, and v is velocity.

Example Calculation

1. Given a 2.0 kg object moving at 3.0 m s⁻¹, calculate its momentum.
2. Use the equation: p = m v = 2.0 kg × 3.0 m s⁻¹ = 6.0 kg m s⁻¹.
3. Answer: p = 6.0 kg m s⁻¹.

Momentum Table

Illustration

Practice Questions

1. Calculate the momentum of a 0.5 kg ball moving at 10 m s⁻¹.
2. What is the momentum of a 3.0 kg object moving at 0 m s⁻¹?