Advertisements
Advertisements
प्रश्न
Give an example when work done by the force of gravity acting on a body is zero even though the body gets displaced from its initial position.
उत्तर
When a coolie carries a load while moving on a ground, the displacement is in the horizontal direction while the force of gravity acts vertically downward. So the work done by the force of gravity is zero.
APPEARS IN
संबंधित प्रश्न
A stone of mass m is rotated in a circular path with a uniform speed by tying a strong string with the help of your hand. Answer the following questions
1) Is the stone moving with a uniform or variable speed?
2) Is the stone moving with a uniform acceleration? In which direction does the acceleration act?
3) What kind of force acts on the hand and state its direction?
What physical quantity does the electron volt (eV) measure? How is it related to the S.I. unit of that quality?
How is kilowatt hour related to joule?
A body, when acted upon by a force of 10 kgf, gets displaced by 0.5 m. Calculate the work done by the force, when the displacement is (i) in the direction of force, (ii) at an angle of 60° with the force, and (iii) normal to the force. (g = 10 N kg-1)
State the factors on which moment of force about a point depends.
What is the work done when the force on the object and the displacement of the object are perpendicular to each other?
Define 1 kgf., How is it related to the S.I. unit of force?
A coolie carries a load of 30 kgf through a distance of 500 m in 5 minutes while another coolie B carries the same load through the same distance in 10 minutes. Compare the
(i) work done, and
(ii) power developed. (Take: g = 10md−2)
A man weighing 700 N runs up a flight of 15 steps, each 20 cm high, in 5 seconds. Calculate the power of the man.
A boy weighing 50 kgf climbs up from the first floor at a height of 3 m above the ground to the third floor at a height of 9 m above the ground. What will be the increase in his gravitational potential energy? (Take g = 10 N kg-1).