A car has a momentum of [tex]$20,000 \, \text{kg} \cdot \text{m} / \text{s}$[/tex]. What would the car's momentum be if its velocity doubles?

A. [tex]$10,000 \, \text{kg} \cdot \text{m} / \text{s}$[/tex]
B. [tex][tex]$20,000 \, \text{kg} \cdot \text{m} / \text{s}$[/tex][/tex]
C. [tex]$40,000 \, \text{kg} \cdot \text{m} / \text{s}$[/tex]
D. [tex]$80,000 \, \text{kg} \cdot \text{m} / \text{s}$[/tex]



Answer :

Certainly! To determine the car's new momentum when its velocity doubles, let's follow the step-by-step process:

1. Understanding Momentum: Momentum ([tex]\( p \)[/tex]) is given by the product of an object's mass ([tex]\( m \)[/tex]) and its velocity ([tex]\( v \)[/tex]). Mathematically, this relationship is expressed as:
[tex]\[ p = m \cdot v \][/tex]

2. Initial Momentum: We are told that the initial momentum of the car is [tex]\( 20,000 \, \text{kg} \cdot \text{m/s} \)[/tex].

3. Doubling the Velocity: If the car’s velocity doubles, we need to determine how the momentum changes. Assume the initial velocity is [tex]\( v \)[/tex]. When the velocity doubles, it becomes [tex]\( 2v \)[/tex].

4. New Momentum Calculation: The new momentum will be the mass of the car times the new velocity. Since the new velocity is [tex]\( 2v \)[/tex], the new momentum ([tex]\( p_{\text{new}} \)[/tex]) will be:
[tex]\[ p_{\text{new}} = m \cdot (2v) \][/tex]

5. Relating New Momentum to Initial Momentum: Notice that since we had the initial momentum [tex]\( p = m \cdot v = 20,000 \, \text{kg} \cdot \text{m/s} \)[/tex], when the velocity doubles, the new momentum will be:
[tex]\[ p_{\text{new}} = 2 \cdot (m \cdot v) = 2 \cdot 20,000 \, \text{kg} \cdot \text{m/s} = 40,000 \, \text{kg} \cdot \text{m/s} \][/tex]

6. Conclusion: The car's momentum would be [tex]\( 40,000 \, \text{kg} \cdot \text{m/s} \)[/tex] if its velocity doubles.

Therefore, the correct answer is:
[tex]\[ \boxed{40,000 \, \text{kg} \cdot \text{m/s}} \][/tex]