Question

A body weighs $7\,N$ on the surface of the earth. How much will it weigh on the surface of a planet whose mass is $1/{7^{th}}$ and radius is half as that of the earth?
A. 4N
B. 7N
C. 2N
D. 1N

Answer 1

To answer this question, we first need to understand what weight is.The weight of an object is defined as the force exerted on it by gravity in science and engineering. The gravitational force exerted on the item is defined as a vector quantity in several mainstream textbooks. Others define weight as a scalar quantity, the gravitational force's magnitude.

Complete step by step answer:
Mass: In physics, mass is a numerical measure of inertia, which is a fundamental feature of all matter. It is, in effect, a body of matter's resistance to a change in speed or position caused by the application of a force. The smaller the change caused by an applied force, the larger the mass of the body.

Gravitational acceleration: The acceleration of an object in free fall within a vacuum is known as gravitational acceleration in physics (and thus without experiencing drag). This is the gradual increase in speed induced only by gravitational attraction. All bodies accelerate in vacuum at the same rate at certain GPS coordinates on the Earth's surface and a particular altitude, regardless of their masses or compositions, gravimetry is the measurement and analysis of these speeds. Formula of weight is,
$W = m \times g$ (Here $m$ is the mass and $g$ are the gravitational acceleration)

As we can see that weight is directly proportional to gravitational acceleration and gravitational force is directly proportional to mass of the planet. So, we can conclude that weight is directly proportional to mass of the planet.So,
$W \propto {\kern 1pt} {\kern 1pt} {\kern 1pt} {M_m}$ (Mass of planet).
So now the planet whose mass is $1/{7^{th}}$ of the mass of the earth.
So, the final weight is $W = \dfrac{1}{7} \times 7N = 1N$

Hence, the final answer is option D.

Note: It determines how much we weigh and how far a basketball travels before returning to the ground when thrown. The force exerted by the Earth on you is equal to the force exerted by the Earth on you. The gravitational force matches your weight when you're at rest on or near the Earth's surface.