English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

You are given leech, Nereis, Scolopendra, prawn and scorpion; and all have segmented body organisation. Will you classify them in one group? If no, give the important characters based on which you will separate these organisms into different groups.

Two balls of the same size but of different materials, rubber and iron are kept on the smooth floor of a moving train. The brakes are applied suddenly to stop the train. Will the balls start rolling? If so, in which direction? Will they move at the same speed? Give reasons for your answer.

What is momentum? Write its SI unit. Interpret force in terms of momentum. Represent the following graphically

(a) momentum versus velocity when mass is fixed.

(b) momentum versus mass when velocity is constant.

In the relation F = `"G M" "m"//"d"^2`, the quantity G

The force of attraction between two unit point masses separated by a unit distance is called

On the earth, a stone is thrown from a height in a direction parallel to the earth’s surface while another stone is simultaneously dropped from the same height. Which stone would reach the ground first and why?

Suppose the gravity of the earth suddenly becomes zero, then in which direction will the moon begin to move if no other celestial body affects it?

How does the force of attraction between the two bodies depend upon their masses and the distance between them? A student thought that two bricks tied together would fall faster than a single one under the action of gravity. Do you agree with his hypothesis or not? Comment.

In the case of negative work, the angle between the force and displacement is

A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. The work done against the gravitational force will be (g = 10 m s^–2)

An automobile engine propels a 1000 kg car (A) along a levelled road at a speed of 36 km h^–1. Find the power if the opposing frictional force is 100 N. Now, suppose after travelling a distance of 200 m, this car collides with another stationary car (B) of the same mass and comes to rest. Let its engine also stop at the same time. Now the car (B) starts moving on the same level road without getting its engine started. Find the speed of the car (B) just after the collision.

A girl with having a mass of 35 kg sits on a trolley of mass 5 kg. The trolley is given an initial velocity of 4 m s^–1 by applying a force. The trolley comes to rest after traversing a distance of 16 m. (a) How much work is done on the trolley? (b) How much work is done by the girl?

The atmosphere of the earth is heated by radiations which are mainly

The two forms of oxygen found in the atmosphere are

Choose the correct sequences

An increase in carbon dioxide content in the atmosphere would not cause

Which one is not a source of carbohydrates?

The crops which are grown in the rainy season are called ______ crops.

Why is organic matter important for crop production?

If there is low rainfall in a village throughout the year, what measures will you suggest to the farmers for better cropping?