A stone is dropped from the adge ofg the roof, find
(i) How long does it take to fall 4.9 m?
(ii) How fast does it move at the end of that fall?
(iii) How fast does it move at the end of 7.9 metres?
(iv) What is its acceleration after 1 s and after 2s?

What are the differences between the mass of an object and its weight?

What happens to the force between two objects, if
(i) the mass of one object is doubled?
(ii) the distance between the objects is doubled and tripled?
(iii) the masses of both objects are doubled?

A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate
(i) the maximum height to which it rises,
(ii) the total time it takes to return to the surface of the earth.

State any three differences between mass and weight.

(i) Write the formula to find the magnitude of gravitational force between the earth and an object on the earth's surface.
(ii) Derive how does the value of gravitational force F between two objects change when
(a) distance between them is reduced to half and
(b) mass of an object is increased four times

Two objects of masses m₁ and m₂ having the same size are dropped simultaneously from heights h₁and h_2' respectively. Find out the ratio of time they would take in reaching the ground. Will this ratio remain the same, if
(i) one of the objects is hollow and the other one is solid and
(ii) both of them are hollow, size remaining the same in each case? Give reason.

(i) list two differences between thrust and pressure.
(ii) What is meant by 1 pascal and 1 newton? How will the pressure change, if area of contact is doubled?

(i) A steel needle sinks in water but a steel ship floats. Explain, how?
(ii) Why do you prefer a broad and thick handle of your suitcase?

(i) Define relative density. Give its mathematical form.
(ii) The mass of an iron cube having an edge length 1.5 em is 50 g. Find its density.
(iii) The volume of a 250 g sealed tin is 400 cubic cm. Find the density of the tin in g (cc)-1. State, if the object would sink or float in water

The radius of the earth at the poles is 6357 km and the radius at the equator is 6378 km. Calculate the percentage change in the weight of a body when it is taken from the equator to the poles.