Advertisements
Advertisements
Questions
Define work.
Define the term work
Advertisements
Solution
The work done by a force on a body is equal to the product of the force applied and the distance moved by the body in the direction of force i.e.,
Work done = Force × distance moved in the direction of force
APPEARS IN
RELATED QUESTIONS
Name a common device where a gear train is used
What is the work done by the moon when it revolves around the earth?
Power spent by a body depends on the time for which it does work.
In which of the following cases is work being done:
- A boy pushing a heavy rock
- A boy climbing up the stairs
- A coolie standing with a box on his head
- A girl moving on the road.
The moon is revolving around the earth in a circular path. How much work is done by the moon?
A boy weighing 25 kgf climbs up from the first floor at height 3 m above the ground to the third floor at height 9m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N kg -1)
Fill in the blank with suitable word :
The work done on a body moving in a circular path is __________
Explain by an example that a body may possess energy even when it is not in motion.
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.
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 :
Determine the amount of work done when an object is displaced at an angle of 30° with respect to the direction of the applied force.
What is meant by a translational motion? Give one example.
What is the ratio of SI units to CGS units of 'work'?
Distinguish between work and power.
A cricket ball is thrown up from the earth's surface. What happens to its P.E.
(a) during the motion
(b) at the highest point?
Name the CGS unit of work.
Give an example
Electrical energy changes of sound energy.
Name two places in India where electricity is generated from nuclear power plants.
A block of mass 30 kg is pulled up a slope, as shown in diagram with a constant speed, by applying a force of 200 N parallel to slope.
A and B are initial and final positions of block.
(i) Calculate the work done by force in moving the block from A to B.
(ii) Calculate P.E. gained by block. [g=10ms-2]
(i) A 200g ball is thrown vertically upward with an initial velocity of 30 ms-1. Draw a velocity-time graph for the motion of ball.
(ii) How long will the ball take to reach the highest point?
(iii) What will be the kinetic energy of ball, when it returns to the starting point, neglecting the air resistance?
(iv) What will be the potential energy of ball at highest point?
An electric motor pump is 60% efficient and is rated 2.5 H.P. Calculate the maximum load it can lift through a height of 10m in 8 sec. (1 H.P. = 750 W).
A bucketful of water is to be drawn from a well ______ will be done when a ______ is applied to do this because there will be a ______ of water.
(displacement, work, force)
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 |
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
Food grains are getting dried in the sun.
