The volume of $50$ g of a substance is $20$ cm$^3$. If the density of water is $1$ g cm$^{-3}$, will the substance float or sink?

A stone is allowed to fall from the top of a tower $100$ m high and at the same time another stone is projected vertically upwards from the ground with a velocity of $25$ m/s. Calculate when and where the two stones will meet.

If the moon attracts the earth, why does the earth not move towards the moon?

Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same when he meets him at the equator. Will the friend agree with the weight of gold bought? If not, why? [Hint: The value of $g$ is greater at the poles than at the equator.]

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

What do we call the gravitational force between the earth and an object?

Gravitational force on the surface of the moon is only $\frac{1}{6}$ as strong as gravitational force on the earth. What is the weight in newtons of a $10$ kg object on the moon and on the earth?

A ball thrown up vertically returns to the thrower after $6$ s. Find (b) the maximum height it reaches, and

What happens to the force between two objects, if (iii) the masses of both objects are doubled?

What happens to the force between two objects, if (ii) the distance between the objects is doubled and tripled?

What is the magnitude of the gravitational force between the earth and a $1$ kg object on its surface? (Mass of the earth is $6 \times 10^{24}$ kg and radius of the earth is $6.4 \times 10^{6}$ m.)

How does the force of gravitation between two objects change when the distance between them is reduced to half ?

A ball thrown up vertically returns to the thrower after $6$ s. Find (c) its position after $4$ s.

What happens to the force between two objects, if (i) the mass of one object is doubled?

In what direction does the buoyant force on an object immersed in a liquid act?

Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall faster than a light object?

Calculate the force of gravitation between the earth and the Sun, given that the mass of the earth = $6 \times 10^{24}$ kg and of the Sun = $2 \times 10^{30}$ kg. The average distance between the two is $1.5 \times 10^{11}$ m.

The volume of a $500$ g sealed packet is $350$ cm$^3$. Will the packet float or sink in water if the density of water is $1$ g cm$^{-3}$? What will be the mass of the water displaced by this packet?

A stone is thrown vertically upward with an initial velocity of $40$ m/s. Taking $g = 10$ m/s$^2$, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone?

The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force that is greater or smaller or the same as the force with which the moon attracts the earth? Why?