Question

The SI unit of momentum is kgm/s
(A) True
(B) False

Answer 1

Hint: The formula for momentum is $$P=mv$$ , where m denotes mass and v denotes velocity.

Complete step by step solution:
Since the formula for momentum is $$P=mv$$, the unit of momentum can be written as
Unit of P = (Unit of mass)(Unit of velocity)
We know that SI unit of mass is Kg and SI unit of velocity is ms^-1, substituting these values in the above equation
Unit of P = (kg)(m/s)
Hence,
Unit of P = kg ms^-1
Comparing it with the given unit in question, we can see that s^-1 should be in the numerator as per the calculated unit, but in the question, it is in denominator, hence the given statement is false

Therefore, the correct answer to the question is option : B

Additional information: While calculating units/dimensions of any quantity, one should always try to convert the quantity using formulas or terms learned in Mechanics. This is because the combination of fundamental quantities like length, mass and time give rise to more numbers of derived quantities than the combination of remaining fundamental quantities. For example, if one needs to calculate the dimension of the magnetic field, then using the formula $$F=iLB$$ is easier than using Biot Savart’s law. And units of force can be calculated using F=ma, which is part of mechanics.

Note: Before attempting to solve the problem, the student needs to clearly look at the question. If one doesn’t carefully observe that the question has s^-1 in the denominator, he/she might assume the statement is true.