English Medium Class 9 - CBSE Question Bank Solutions for Science

What should be the angle between the direction of force and the direction of motion of a body so that the work done is zero?

In which of the following case the work done by a force will be maximum : when the angle between the direction of force and direction of motion is 0° or 90°?

How much work is done by the gravitational force of earth acting on a satellite moving around it in a circular path? Give reason for your answer.

A max X goes to the top of a building by a vertical spiral staircase. Another man Y of the same mass goes to the top of the same building by a slanting ladder. Which of the two does more work against gravity and why?

A boy tries to push a truck parked on the roadside. The truck does not move at all. Another boy pushes a bicycle. The bicycle moves through a certain distance. In which case was the work done more : on the trick or on the bicycle? Give a reason to support your answer.

In 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. If the value of g be 10 m/s², the work done by the girl against the gravitational force will be :

The work done on an object does not depend on the :

Each of the following statement describes a force acting. Which force is causing work to be done?

A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 m s⁻², the work by her after climbing 2 m will be :

Prepare a flow chart of various natural resources.

Which of the following cannot transmit sound? Water, Vacuum, Aluminium, Oxygen gas

What is the general name of the waves consisting of :
(a) compressions and rarefactions?
(b) crests and troughs?