English Medium Class 9 - CBSE Question Bank Solutions

What is the quantity which is measured by the area occupied below the velocity-time graph?

Which of the following has more inertia:

1. a rubber ball and a stone of the same size?
2. a bicycle and a train?
3. a five-rupees coin and a one-rupee coin?

In the following example, try to identify the number of times the velocity of the ball changes:

“A football player kicks a football to another player of his team who kicks the football towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team”.

Also identify the agent supplying the force in each case.

Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.

Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

Why is it advised to tie any luggage kept on the roof of a bus with a rope?

What is the momentum of an object of mass m, moving with a velocity v?

Why does an object float or sink when placed on the surface of water?

Why does a block of plastic released under water come up to the surface of water?

The volume of 50 g of a substance is 20 cm³. If the density of water is 1 g cm⁻³, will the substance float or sink?

The volume of a 500 g sealed packet is 350 cm³. 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?

What are the various energy transformations that occur when you are riding a bicycle?

An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m s⁻¹?

Does sound follow the same laws of reflection as light does? Explain.

When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?

What name is given to the product of mass and velocity of a body ?

What does the slope of a speed-time graph indicate ?

What can you say about the motion of a body if its speed-time graph is a straight line parallel to the time axis ?

What will be the momentum of a body of mass ‘m’ which is moving with a velocity V ?

What conclusion can you draw about the acceleration of a body from the speed-time graph shown below .