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प्रश्न
Work done = Force × ........................................
उत्तर
Work done = Force ×distance moved in direction of force.
APPEARS IN
संबंधित प्रश्न
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.
In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east, as shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.
An electron emitter must have _____________ work function and ___________ melting point.
A coolie does no work against the force of gravity while carrying a luggage on a road.
What are the two kinds of mechanical energy?
A bullet of mass 0.5 kg slows down from a speed of 5 m s-1 to that of 3 m s-1. Calculate the change in kinetic energy of the ball.
What is the condition for a force to do work on a body?
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 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 :
What is the work done when the object acted upon by a force remains at rest?
Give two examples of work done.
A machine raises a load of 750 N through a height of 16 m in 5s. calculate:
(i) work done by machine,
(ii) power at which the machine works.
What do you understand by 'potential energy' and 'Kinetic energy'? Give three examples of each to illustrate your answer.
Fill in the boxe to show the corresponding energy transformation.
A canon ball of mass 500g is fired with a speed of 15m/s-1. Find: its momentum.
Can two agents, doing the same work, have different power?
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?
Who is the odd one out?
