Question

The mass of a body
(A) Is slightly different at different places on earth
(B) Is independent of the free-fall acceleration
(C) Is the same for all bodies of the same volume
(D) Can be measured most accurately on a spring scale

Answer 1

Hint The mass of a body is a constant which defines the inertial properties of matter. The mass of a body is the ratio of the force applied to it with the acceleration produced in the body due to that force. Mass depends on the number of atoms present in a body.

Complete Step by step solution
On analyzing all the given options one by one, we have-
Option (A) The mass of the body is constant and does not depend on the gravitational field. Instead, weight is the property that depends on the gravitational field around it. Due to irregularity in the gravitational field of the earth, the weight of an object is slightly different at different places on earth. Thus, this statement is not correct.
Option (B) The free-fall acceleration, or g is the acceleration produced in an object when it is attracted towards the earth and falls freely towards it. The gravitational acceleration depends on the mass of the planet (earth), the distance between the body and the planet’s center of mass. It does not depend on the mass of the body, this means that all objects are equally attracted towards earth, irrespective of their mass. Thus, this statement is correct.
Option (C) Volume is a measure of how much space is occupied by a body. The mass of the body however depends on the amount of matter contained in the body rather than the space occupied by it. Therefore, objects of different densities can have different masses for the same volume. Thus, this statement is not correct.
Option (D) A spring scale is used to measure the weight of a body. Although weight depends on the mass of a body, it can change with the gravitational field. So if the acceleration due to gravity (g) is known, the mass of an object can be determined by its weight but it is not the most accurate method as the weight can change at different places.

Option (B) is the only correct option.

Note Mass and weight are very often confused with each other, but both are very different terms. The weight is the force with which an object is attracted towards earth (or any other planet) whereas mass is not a force it is a property of a material.