English Medium इयत्ता ९ - CBSE Question Bank Solutions for Science

Fill in the blank with suitable word :
Work is measured as a product of __________ and __________

Fill in the blank with suitable word : 
The work done on a body moving in a circular path is __________

Fill in the blank with suitable word :
1 joule is the work done when a force of 1 __________ moves an object through a distance of one __________ in the direction of __________.

What are the quantities on which the amount of work done depends? How are they related to work?

Is it possible that a force is acting on a body but still the work done is zero? Explain giving one example.

A boy throws a rubber ball vertically upwards. What type of work, positive or negative, is done : by the force applied by the boy?
(a) by the force applied by the boy?
(b) by the gravitational force of earth?

Write the formula for work done on a body when the body moves at an angle to the direction of force. Give the meaning of each symbol used.

Give one example in which a force does zero work.

If the work done by a force in moving an object through a distance of 20 cm is 24.2 J, what is the magnitude of the force?

A car is being driven by a force of 2.5 ✕ 10¹⁰ N. Travelling at a constant speed of 5 m/s, it takes 2 minutes to reach a certain place. Calculate the work done.

How much work is done when a force of 1 N moves a body through a distance of 1 m in its own direction?

Write the formula for the work done on a body when a force acts on the body in the direction of its displacement. Give the meaning of each symbol which occurs in the formula.

A person of mass 50 kg climbs a tower of height 72 metres. Calculate the work done. (g = 9.8 m s⁻²).

When do we say that work is done? Write the formula for the work done by a body in moving up against gravity. Give the meaning of each symbol which occurs in it.

How much work is done when a force of 2 N moves a body through a distance of 10 cm in the direction of force?

What happens to the work done when the dispacement of body is at right angles to the direction of force acting on it? Explain your answer.

A force of 50 N acts on a body and moves it a distance of 4 m on horizontal surface. Calculate the work done if the direction of force is at an angle of 60° to the horizontal surface.

The work done by a force acting obliquely is given by the formula : W = F cos θ ✕ s. What will happen to the work done if angle θ between the direction of force and motion of the body is increased gradually? Will it increase, decrease or remain constant.