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प्रश्न
State the S.I. unit of energy.
उत्तर
S.I. unit of energy Joule (J).
संबंधित प्रश्न
When do we say that work is done?
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
A sailboat is moving due to wind energy.
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.
A coolie does no work against the force of gravity while carrying a luggage on a road.
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 man lifts a mass of 20 kg to a height of 2.5 m. Assuming that the force of gravity on 1 kg mass is 10 N, find the work done by the man.
State the energy transformation on the following:
Electricity is obtained from solar energy.
State the law of conservation of energy.
What is the work done against gravity when a body is moved horizontally along a frictionless surface?
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 __________.
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.
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 :
Each of the following statement describes a force acting. Which force is causing work to be done?
Ravi applied a force of 10 N and moved a book 30 cm in the direction of the force. How much was the work done by Ravi?
Name the physical quantity whose SI unit is Nm.
State the conditions of equilibrium for a rigid body.
A uniform circular motion is an accelerated motion. Justify it.
Complete the following sentences:
1 H.P. = ........ W.
A block of mass 20 kg is pulled up a slope (fig.12) with a constant speed by applying a force of 500 N parallel to the slope. A and B are initial and final positions of the block.
(a) Calculate the work done by the force in moving the block from A and B.
(b) Calculate the potential energy gained by the block.
Define energy and state the unit of energy and the law of conservation of energy.
State the energy changes which take place when A toy car with a wound spring moves on ground.
Give an example
Chemical energy changes to heat energy.
A coolie, with a load of 30 kg on his head, walks on the platform. If he walks a distance of 60 m, what is the work done by him?
In the following case write yes, if the work is being done and no if no work is being done.
A boy climbing up a staircase.
State larger units of power.
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]
One labourer carried four pans of road metal through a distance of 100 metres. If he carries two pans of road metal through a 200 metre distance ______ work will be done.
What is work?
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.
