Which physical quantity is obtained by the ratio of momentum and velocity of…
2018
Which physical quantity is obtained by the ratio of momentum and velocity of matter?
Answer: B. Mass — Momentum of a moving body is defined as the product of its mass and its velocity, expressed by the identity p = m x v, where m is the mass and v is the…
- A.
Acceleration
- B.
Mass
- C.
Velocity
- D.
Force
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Correct answer: B
Momentum of a moving body is defined as the product of its mass and its velocity, expressed by the identity p = m x v, where m is the mass and v is the velocity. This identity holds for any moving object, independent of its particular mass or speed.
Start from the momentum identity, p = m x v.
Divide both sides by the velocity v: p / v = (m x v) / v = m, since the velocity terms cancel.
So dividing the momentum of the matter by its velocity returns the quantity mass.
This also checks out dimensionally: momentum carries the unit kg.m/s while velocity carries the unit m/s. Dividing kg.m/s by m/s cancels the m/s term and leaves kg, the SI unit of mass -- confirming the same result independently.