Gravitation Test - 11

When a body moves in an orbital path, it experiences a force away from the center of the orbital path. The gravitational force acting on a planet or a satellite balances this outward force experienced by the body because of revolution. Therefore, gravitational force is responsible for keeping the planets and the satellites moving in their respective orbits.

The correct answer is D.

Why alternative A is wrong:

Electrical force acts only in a short range. The distances between the celestial bodies are very large. Therefore, effectively, no electrical force acts between them.

Why alternative B is wrong:

Magnetic force is a short range force. The distances between the celestial bodies are very large. Therefore, effectively, no magnetic force acts between them.

Why alternative C is wrong:

Frictional force acts only when two bodies are in contact with each other. Celestial bodies are at great distances from each other. Therefore, frictional force cannot act between them.

Mass is the measurement of the amount of material present in an object. It is an intrinsic property of the object. It does not depend on its location and position. Hence, the ball’s mass on Jupiter will be the same as it is on Earth, i.e. 10 kg.

The weight of an object is a measure of the force exerted by gravity on it. The gravitational pull exerted by Jupiter is more than that exerted by Earth. Hence, the ball’s weight will be more on Jupiter than it is on Earth, i.e., more than 98 N.

The correct answer is B.

In this question, the student should first calculate Mark’s mass on Earth and then use this value to calculate his weight on Neptune.

Mark’s weight on Earth = 98 N

Value of g on Earth = 9.8 ms^-2

Mark’s mass on Earth $\frac{98 \text{N}}{9.8 {\text{ms}}^{-2}}=\frac{{\displaystyle 98 {\text{Kgms}}^{-2}}}{{\displaystyle 9.8 {\text{ms}}^{-2}}}=10\text{Kg}$

Therefore, Mark’s weight on Neptune ${\text{=10 Kg ×10.78 ms}}^{-2}{\text{=107.8 Kgms}}^{-2}\text{=107.8N}$

The correct answer is C.

$\text{Weight = Mass × Gravity}$

$\text{Mass of Nancy = }\frac{\text{Weight}}{\text{Gravity}}\text{=}\frac{45}{10}\text{=4.5Kg}$

Therefore, Nancy’s weight on Jupiter $=4.5 \text{Kg} \times (2.6 \times 10){\text{ms}}^{-2} = 117 {\text{Kgms}}^{-2}\text{ =117 N}$

The correct answer is D.