Advertisements
Advertisements
प्रश्न
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?
Advertisements
उत्तर
The relation between work, force, distance and angle between the two is:
W = (F) (S) cos θ
Where,
(W) - Work done
(F) - Force
(S) - Displacement
(θ) - Angle between force and displacement
When the force is perpendicular to the direction of motion, and hence, the work done is also zero.
Example - The work done by the earth on a satellite moving in a circular orbit around it is zero.
संबंधित प्रश्न
When do we say that work is done?
An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?
Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?
An electron emitter must have _____________ work function and ___________ melting point.
Write the expression for work done by a force.
A weight lifter lifted a load of 200 kgf to a height of 2.5 m in 5 s. Calculate:
- the work done, and
- the power developed by him. Take g = 10 N kg-1
In case of negative work, the angle between the force and displacement is :
What is meant by a translational motion? Give one example.
A boy does work when he pushes against a brick wall. (yes/no).
What is the ratio of SI units to CGS units of 'work'?
Give two examples of work done.
A weight lifted a load of 200 kgf to a height of 2.5 m in 5 s. calculate: (i) the work done, and (ii) the power developed by him. Take g= 10 N kg-1.
A 100 W electric lamp emits energy in the form of light at the rate 10 J per second. What percentage of electric energy does the lamp transform into light energy?
Calculate the amount of work done by a child carrying a bag of 20 kg when he moves a distance of 40 m in
(a) Vertical direction, and
(b) Horizontal direction
Give an example
Electrical energy changes to heat energy.
A force can cause an object to change its ______.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A wind-mill is lifting water from a well.
