English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

A body of mass 25 kg has a momentum of 125 kg.m/s. Calculate the velocity of the body.

Calculate the momentum of the following :
(a) an elephant of mass 2000 kg moving at 5 m/s
(b) a bullet of mass 0.02 kg moving at 400 m/s

Describe the term ‘inertia’ with respect to motion.

On what factor does the inertia of a body depend ? Which has more inertia, a cricket ball or a rubber ball of the same size ?

Why do the passengers in a bus tend to fall backward when it starts suddenly ?

Explain why, a person travelling in a bus falls forward when the bus stops suddenly.

When a tree is shaken, its fruits and leaves fall down . Why ?

If the mass of a body and the force acting on it are both doubled, what happens to the acceleration ?

Draw a velocity-time graph to show the following motion :
A car accelerates uniformly from rest for 5 s ; then it travels at a steady’ velocity for 5 s.

The velocity-time graph for part of a train journey is a horizontal straight line. What does this tell you about the trains velocity.

The velocity-time graph for part of a train journey is a horizontal straight line. What does this tell you about its acceleration ?

Show by means of graphical method that: v = u + at, where the symbols have their usual meanings.

Show by using the graphical method that: `s=ut+1/2at^2` where the symbols have their usual meanings.

Derive the following equation of motion by the graphical method : v² = u² + 2as, where the symbols have their usual meanings.

What can you say about the motion of a body if:
its displacement-time graph is a straight line ?

What can you say about the motion of a body if:
its velocity-time graph is a straight line ?

A body with an initial velocity x moves with a uniform acceleration y. Plot its velocity-time graph.

Given alongside is the velocity-time graph for a moving body :
Find :
(i) Velocity of the body at point C.
(ii) Acceleration acting on the body between A and B.
(iii) Acceleration acting on the body between B and C.

A body is moving uniformly in a straight line with a velocity of 5 m/s. Find graphically the distance covered by it in 5 seconds.

The speed-time graph of an ascending passenger lift is given alongside. What is the acceleration of the lift:
(1) during the first two seconds ?
(2) between second and tenth second ?
(3) during the last two seconds ?