Introduction to Gravitation

Why there are no tides in the lakes?

What is the universal law of gravity?

The weight of a person on the earth is $80 \mathrm{kg} \mathrm{wt}$. Its weight on the moon is $128 \mathrm{N}$. Mass of the moon is $7.34\times {10}^{22} \mathrm{kg}$, the radius of the moon is $1.75\times {10}^6 \mathrm{m}$. What is the value of the gravitational constant?

What is the mass of earth?

If one of the mass is tripled and the distance between them made $3/2$ times. Find the effect of force of attraction?

State the equation of gravitational force.

Is gravitational force acting on electricity?

How do earth maintain its axis tilt?

The mass of the earth is $6\times {10}^{24} \mathrm{kg}$ and that of the moon is $7.4\times {10}^{22} \mathrm{kg}$. If the distance between the earth and the moon is $3.84\times {10}^5 \mathrm{km}$, calculate the force exerted by the earth on the moon. $\left(\mathrm{Take} G=6.7\times {10}^{-11} {\mathrm{Nm}}^2{\mathrm{kg}}^{-2}\right)$

Assertion:  Areal speed of planets moving around the sun remains constant.

Reason:  Gravitational force between planet and sun provides required centripetal force to the planet for revolution around the sun.

The value of the universal gravitational constant is _____$\times {10}^{-11} \mathrm{N} {\mathrm{m}}^2 {\mathrm{kg}}^{-2}$. (Answer upto two decimal places).

If distance between objects is doubled, the force of gravitation between them becomes _____ ($\frac{1}{2}/\frac{1}{4}$).

Force of _____ (gravitation/acceleration) is responsible for motion of planets around the sun.

The motion of the moon around the earth is due to _____ (gravitational/frictional) force.

Gravitation is a _____ (highest/lowest) range force.

In S.I. unit $G$ = _____.

State Newton's Law of Gravitation.

Why does earth revolve around sun and not move towards sun? Derive an expression for force between sun and earth.

How does force of attraction between two objects depend on their masses and distance between them? A student thought that two bricks tied together would fall faster than a single one under the action of gravity. Do you agree with this hypothesis? Discuss.

If gravitational force of earth suddenly vanished away, what would happen? In which direction will the objects move, if not towards centre of earth?