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Define Gravity

Define Gravitation

Define acceleration due to gravity

State Newton’s Law of Gravitation

What is weight?

Give Reasons for the Following:

The weight of a body is zero at the centre of the earth

Why does the moon not actually fall on the surface of the earth?

Why is the weight of an object on the moon one-sixth its weight on the earth?

As we go higher above the surface of the earth the weight of the body decreases

If the force of gravity acts on all bodies proportional to their masses, why does a heavy body not faster than a light body?

Differentiate between mass and weight.

Under what conditions a body becomes weightless?

If we go deeper inside the earth, what will change: weight or mass or both, why?

Give at least two points of difference between G and g.

A body is taken from the surface of the earth to the moon. Will its weight increase or decrease? Justify your answer.

State Newton’s law of gravitation. Explain it.

Derive an expression for the acceleration due to gravity on the surface of the earth. State the factors on which g depends. How does it vary with depth? Where is it maximum on the surface of the earth?

A boy drops a stone from a cliff which reaches on the ground in B seconds. Calculate

(i) height of cliff

(ii) final velocity of the stone

A stone thrown vertically upwards takes 3 seconds to attain maximum height, calculate

(i) initial velocity of stone

(ii) maximum height attained by the stone

Prove that if a body is thrown vertically upwards, then the time of ascent is equal to the time of descent.

A ball is thrown vertically upwards with a velocity u. Calculate thevelocity with which it falls to the earth again.

What is the mass of an object whose weight is 98 N?

Why will a sheet of paper fall slower than one that is crumpled into a ball?

If the force of gravity somehow vanished away, why would we be sent flying into space?

Where will you weigh more: at the equator or at the poles?

Is the acceleration due to gravity same everywhere on the surface of the earth?

Does acceleration due to gravity depend upon the mass of the body?

Force of gravitation between two bodies varies r with as:

At maximum of the locations the value of ‘g’ is a maximum:

A stone is dropped from the top of the tower. Its speed after it has fallen 20 m is (Take g = 10 ms^{-2})

A ball is thrown vertically upward, acceleration due to gravity is:

At the top of its path a projectile:

Consider earth to be a homogeneous sphere, Scientist A goes deep down in a mine and scientist B goes high up in a balloon. The acceleration due to gravity as measured by:

Which of the following is the evidence to show that there must be a force acting on the earth and directed towards the sun?

If the earth stops rotating the value of ‘g’ at the equator will:

It is found that weight of an object is more at the poles than at the equator. So it is beneficial to purchase goods at the equator and sell them a the poles, provided:

The value of gravitational constant depends upon:

The acceleration due to gravity on the surface of a planet whose mass and radius are both one-third of the Earth (acceleration due to gravity on the earth is g):

In vacuum all freely falling objects:

When a spaceship is two earth radii distant from the centre of the earth, its gravitational acceleration is:

If a planet existed whose mass and radius were both half that of the earth, the acceleration due to gravity at its surface would be:

A stone is dropped from a cliff. Its speed after it has fallen 100 m is:

A ball is thrown up and attains a maximum height of 100 m, it is thrown upwards with a speed of:

A stone dropped from a certain height takes 4 second to reach the ground. The height is:

The weight of an object:

The equation is valid only for:

If the distance between two objects is doubled, the gravitational force between them:

A bomb is released from an aircraft. Its trajectory is:

A soft drink bottle is dropped by a water from the top of a hotel whose height is 100 m. It takes T second to reach the ground. Where will it be at T/2 second?

Two bodies, one held 1 m vertically above the other, are released simultaneously and fall freely under gravity. After 2 second, the relative separation of the bodies will be:

Write true or false for the following statements:

The force of attraction between two bodies is called gravity.

The value of G depends upon the mass of two objects.

If a spring balance, holding a heavy object is released, it will read zero weight.

The value of G is high if the radius of the body is more and less if radius is less.

The centre of mass and centre of gravity for a small body lie at the same point.

The gravitational force between two bodies’ changes if a material body is placed between them.

The acceleration of a body thrown up is numerically the same as the acceleration of a downward falling body but opposite in sign.

The value of g is zero at the centre of the earth.

The inertia of an object depends upon its mass.

All objects attract each other along the line joining their centre of mass

Acceleration due to gravity is expressed as

g =

Where, symbols have their usual meanings.