(English Medium) ICSE Class 9 - CISCE Question Bank Solutions

A car accelerates to a velocity of 30 m/s in 10 s and then decelerates for 20 s so that it stops. Draw a velocity-time graph to represent the motion and find:
Distance travelled

Figure represents graphically the velocity of a car moving along a straight road over a period of 100 hours.

Calculate the acceleration along AB and the retardation along BC.

A piece of wax floats in brine. What fraction of its volume will be immersed?
R.D. of wax = 0.95, R.D. of brine = 1.1.

Calculate the mass of a body whose volume is 2m³ and relative density is 0.52.

A piece of metal weighs 44.5 gf in air, 39.5 gf in water. What is the R.D. of the metal?

A body of volume 100 cm³ weighs 1 kgf in air. Calculate its weight in water. What is its relative density?

An aeroplane is moving uniformly at a constant height under the action of two forces (i) Upward force (lift) and (ii) Downward force (weight). What is the net force on the aeroplane?

A tennis ball and a cricket ball , both are stationary. To start motion in them .

Define linear momentum and state its S.I. unit.

A body of mass m moving with a velocity v is acted upon by a force. Write an expression for change in momentum in each of the following cases: (i) When v << c, (ii) When v → c and (iii) When v << c but m does not remain constant. Here, c is the speed of light.

Show that the rate of change of momentum = mass × acceleration. Under what condition does this relation hold?

Two bodies A and B of same mass are moving with velocities v and 2v, respectively. Compare their (i) inertia and (ii) momentum.

Two balls A and B of masses m and 2 m are in motion with velocities 2v and v, respectively. Compare:

(i) Their inertia.

(ii) Their momentum.

(iii)  The force needed to stop them in the same time.

State the Newton's second law of motion. What information do you get from it?

Write the mathematical form of Newton's second law of motion. State the conditions if any.