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प्रश्न
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उत्तर
The parameters that can change the kinetic energy are:
(i) Mass
(ii) Speed
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संबंधित प्रश्न
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.
State two disadvantages of producing hydroelectricity.
State the law of conservation of energy.
What are the units of (a) work, and (b) energy?
Why is the work done on an object moving with uniform circular motion zero?
P, Q and R are three forces which act as shown in fig.
The point O lies in the same plane. Given, P = Q = R = 10N
(i) Which force has the least moment about O? Give a reason.
(ii)Which force has the greatest moment about O? Give a reason.
Write an expression for work done by a force depends?
A truck driver can load oil drums into the back of the truck by pushing them up a sloping plank, or by lifting them directly. Each drum has a mass of 80 kg, the plank is 3 m long, and the back of the truck is 0.8 m above the ground.
(i) How much force would be needed to lift a drum into the truck directly/without using the plank? (Take g = 10 m/s2)
(ii) How much energy would be required in lifting the drum into the truck without the plank?
(iii) If the force needed to push the drum up the plank is 300 N, why is this less than the answer to part (i)?
(iv) When the truck is loaded, the driver drives off. List the major energy changes that take place in moving the truck.
(v) The driver has to stop at the factory gates. What happens to the kinetic energy of the truck?
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)
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
Suma is swimming in a pond.
