Question

If the mass of a body is 5 kg, what is its weight?
(A) 49N
(B) 5 N
(C) 49 kg wt
(D) None of these

Answer 1

Hint: Weight of a body is actually a force exerted on the mass of the body by the acceleration due to gravity. Weight of a place is actually a product of mass and acceleration due to gravity.

Complete step by step solution:
Given:
Mass of the body (m) $= 5 kg$
Acceleration due to gravity of the earth (g) $= 9.8 m/s^2$
Since,
Weight of the body is (w) = mg
\[ \Rightarrow {\text{W}} = (5 \times 9.8){\text{ N}}\]
\[\therefore {\text{ W = 49 N}}\]

Hence, Option (A) is the correct answer.

Note: Students often confuse with the mass and weight of a body, so in order to avoid the confusion between them one should keep the points of difference between mass and weight.
Mass:-
1. Mass is the amount of substance or matter present in a body.
2. It is a fundamental quantity.
3. It does not depend upon the acceleration due to gravity of a place.
4. The SI unit of mass of the body is Kilogram. It is denoted by kg.
Weight:-
1. Weight is the measurement of gravitational force acting on a given body.
2. It is a derived quantity.
3. It depends upon the acceleration due to gravity of a place.
4. The SI unit of weight of the body is Newton. It is denoted by N.