English Medium Class 9 - CBSE Question Bank Solutions for Science

Do action and reaction act on the same body or different bodies ? How are they related in magnitude and direction ? Are they simultaneous or not ?

If a man jumps out from a boat, the boat moves backwards. Why ?

Why is it difficult to walk on a slippery road ?

Explain why, a runner presses the ground with his feet before he starts his run.

Draw a diagram to show how a rocket engine provides a force to move the rocket upwards. Label the diagram appropriately.

Name the law involved in the following situation :

when person A standing on roller skates pushes another person B (also standing on roller skates) and makes him move to the right side, then the person A himself gets moved to the left side by an equal distance.

State Newton’s third law of motion and give two examples to illustrate the law.

Explain why, when a fireman directs a powerful stream of water on a fire from a hose pipe, the hose pipe tends to go backward.

The density of gold is 19 g/cm³. Find the volume of 95 g of gold.

What is the mass of 5 m³ of cement of density 3000 kg/m³ ?

What is the density of a substance of mass 100 g and volume 10 cm³ ?

What is the difference between the density and relative density of a substance ?

If the relative density of a substance is 7.1, what will be its density in SI units ?

Calculate the density of an object of volume 3 m³ and mass 9 kg. State whether this object will float or sink in water. Give reason for your answer.

Write down an equation that defines density.

5 kg of material A occupy 20 cm³ whereas 20 kg of materia! B occupy 90 cm³. Which has the greater density : A or B ? Support your answer with calculations.

Define density. What is the SI unit of density ?

Define relative density. What is the SI unit of relative density ?

The density of turpentine is 840 kg/m³. What will be its relative density ? (Density of water = 1000 kg/m³)

A piece of steel has a volume of 12 cm³, and a mass of 96 g. What is its density in g/cm³ ?