Select the best answer for the question.
An object with a mass of 120 kilograms is moving at a velocity of 60 m/s. What's its momentum?
A. 2 kg-m/s
B. 7,200 kg-m/s
C. 0.5 kg-m/s
D. 3,600 kg-m/s
Answer (2)
State the formula for momentum: p = m × v .
Substitute the given values: p = 120 kg × 60 m/s .
Calculate the momentum: p = 7200 kg m/s .
The momentum of the object is 7 , 200 kg-m/s .
Explanation
Understanding the Problem We are given the mass and velocity of an object and asked to find its momentum. Momentum is a measure of how much 'oomph' an object has when it's moving. The more mass and velocity an object has, the more momentum it has!
Stating the Formula The formula for momentum ( p ) is given by: p = m × v where m is the mass of the object and v is its velocity.
Substituting the Values We are given:
Mass, m = 120 kg
Velocity, v = 60 m/s Now, we substitute these values into the momentum formula: p = 120 kg × 60 m/s
Calculating the Momentum Calculating the momentum: p = 7200 kg m/s So, the momentum of the object is 7,200 kg-m/s.
Selecting the Correct Answer Comparing our calculated momentum with the given options, we see that option B matches our result. Therefore, the correct answer is B.
Examples
Understanding momentum is crucial in many real-world scenarios, especially in sports and vehicle safety. For instance, when a football player tackles another player, the momentum of the players determines the impact force. Similarly, in car crashes, the momentum of the vehicles involved plays a significant role in determining the severity of the collision. By understanding momentum, engineers can design safer vehicles and athletes can improve their performance and safety on the field.
The momentum of the object is calculated using the formula p = m × v . Substituting the given mass (120 kg) and velocity (60 m/s) yields a momentum of 7,200 kg-m/s, making option B the correct choice.
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