Question

Rank the following in terms of increasing momentum:
A. a 10,000 kg train car at rest
B. a 100 kg person running at 5 m/s
C. a 1200 kg car going 15 m/s
D. a 15 kg meteor going at a speed of 1000 m/s

Answer 1

It’s b because if you’re running at 5 miles per second being a 100kg weight is the fastest

Answer 2

Based on increasing momentum, the given equations are ranked as following,

1. A 1200 kg car going 15 m/s with momentum 18000  kgm/s.

2. A 15 kg meteor going at the speed of 1000 m/s with momentum 15000 kgm/s.

3. A 100 kg person running at 5 m/s with momentum 500 kgm/s.

4. A 10,000 kg train car at rest with zero momentum.

Explanation:

Momentum is the mass in motion i.e. an object is said to have momentum when it is in motion. The momentum of the object depends upon the mass and the velocity of the object. It is vector quantity since it has both direction and magnitude. The momentum can be evaluated using the formula,

$\vec{p}=m \times \vec{v}$

where $\vec{p}$ is the momentum,m is the mass and $\vec{v}$ is the velocity of the object

Momentum of given cases,

A) A train car at rest: The momentum of an object at rest is always 0.

B) A 100kg person running at 5 m/s: $\vec{p}=m \times \vec{v}=100\ \mathrm{kg} \times 5\ \mathrm{m} / \mathrm{s}=500\ \mathrm{kgm} / \mathrm{s}$

Therefore, momentum of the person is 500 kgm/s.

C) A 1200kg car going at 15m/s: $\vec{p}=m \times \vec{v}=1200\ \mathrm{kg} \times 15 \frac{\mathrm{m}}{\mathrm{s}}=18000\ \mathrm{kgm} / \mathrm{s}$  

Therefore, momentum of the person is 18000 kgm/s.

D) A 15 kg meteor going at the speed of 1000m/s:

$\vec{p}=m \times \vec{v}^=15\ \mathrm{kg} \times 1000\ \mathrm{m} / \mathrm{s} =15000\ \mathrm{kgm} / \mathrm{s}$

Therefore, momentum of the meteor is 15000 kgm/s.