Question

When a body is taken from poles to equator on the earth, its weight
A. Increases
B. Decreases
C. Remains the same
D. Increases at south pole and decreases at north pole

Answer 1

Hint: The shape of earth is not exactly a perfect sphere and due to the difference in distances from the center of the earth at the poles and at the equator, the force of gravity is different. Here we will analyze that difference to get the correct answer. The centrifugal force due to rotation of earth about its own axis also plays a part here.

Complete answer:
The shape of the earth is not a perfect sphere. It is bulged at the equator. Most experts believe that this bulge could have been due to the rotation of earth on its own axis and the centrifugal force due to this pushed some of the material that makes up our planet outwards. So as the radius at the equator is more and the force of gravity is inversely proportional to the square of the radius, the force of gravity that acts on you is less there. So, you will weigh a bit less at the equator.

The bulging at the equator is highly exaggerated here and still it is not observable here, this will tell you about the bulge on earth.

The rotation of earth about its own axis also produces a centrifugal force on the body. This effect will further reduce the weight of the body. So due to both these effects the weight of the body when it is taken from poles to equator on the earth decreases.

So, the correct answer is “Option B”.

Note:
It must be noted that although the weight of the body is less at the equator than at the poles. The change is not very high, it is less than 1%. Also, weight must not be confused with mass. The weight of the body is the amount of gravitational force acting on it which can change. But the mass of the body always remains constant.