Advertisements
Advertisements
Question
Solution
APPEARS IN
RELATED QUESTIONS
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (see the given figure). Let us take it that the force acts on the object through the displacement. What is the work done in this case?
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
Can there be displacement of an object in the absence of any force acting on it? Think. Discuss this question with your friends and teacher.
An electron emitter must have _____________ work function and ___________ melting point.
A coolie is moving on a road with a luggage on his head. Does he perform work against the force of gravity? Give reason for your answer.
A boy of weight 40 kgf climbs up the 15 steps, each 15 cm high in 10 s and a girl of weight 20 kgf does the same in 5 s. Compare:
- the work done, and
- the power developed by them. Take g = 10 N kg-1.
State two disadvantages of producing hydroelectricity.
Fill in the blank with suitable word :
The work done on a body moving in a circular path is __________
A person of mass 50 kg climbs a tower of height 72 metres. Calculate the work done. (g = 9.8 m s−2).
Give two examples of couple action in our daily life.
A man lifts a mass of 10 kg from the floor to a shelf 4 meter high. If g = 10 ms-2, what is the work done?
When you move upstairs, do you perform some work?
Give an example
Electrical energy changes to heat energy.
Explain, why submarines are able to dive underwater as well as a sail on the surface of the water?
________ is said to be done when a force is acting on it.
Mention whether work is done or not in the following activity.
| S. No | Activity | Work done or not done |
| 1. | Pushing the door | |
| 2. | Holding a doll | |
| 3. | Sitting in a bus | |
| 4. | Pushing a wall | |
| 5. | Digging soil |
Force acting on a particle moving in a straight line varies with the velocity of the particle v as F = `K/v`, where K is a constant. The work done by this force in time t is
