Example: Calculating the momentum of a slow-moving object

A 1971 Ford Pinto is observed to moving with a velocity of $\langle 22.35, 0, 1.06\rangle\dfrac{m}{s}$. Determine the momentum of this sweet ride.

You need to compute the momentum of a 1971 Ford Pinto using the information provided and any information that you can collect or assume.

• The Ford Pinto is in motion
• It has a velocity, $\vec{v}_{car} = \langle 22.35, 0, 1.06\rangle\dfrac{m}{s}$.

• The mass of the Ford Pinto is not given, but can be found online ($m_{car} = 884.05 kg$).

• The Ford Pinto experiences several forces, but over the short time we are looking at it, it experiences no net force, so its velocity will remain unchanged.
• The velocity of the Ford Pinto is much less than the speed of light ($|\vec{v}_{car}| \ll c = 3.00\times10^8 \dfrac{m}{s}$).

• The momentum of the Ford Pinto is given by $\vec{p} = m \vec{v}$.

We compute the momentum vector.

$$\vec{p}_{car} = m_{car} \vec{v}_{car} = (884.05 kg) \langle 22.35, 0, 1.06\rangle\dfrac{m}{s} = \langle 1.98 \times 10^4, 0, 9.37 \times 10^2\rangle \dfrac{kg\:m}{s}$$