Advertisements
Advertisements
प्रश्न
In which one of the following cases is the work done more? When the angle between the direction of motion and that of the force is (i) 90° (ii) 0°.
Advertisements
उत्तर
When the angle between the direction of motion and that of the force is 90°;
W = Fd cos 90° = 0
When the angle between the direction of motion and that of the force is 0°;
W = Fd cos 0° = Fd
Hence in the second case, when the angle is 0°; the work done is more.
APPEARS IN
संबंधित प्रश्न
Give the expression for mechanical advantage of an inclined plane in terms of the length of an inclined plane.
A man having a box on his head, climbs up a slope and another man having an identical box walks the same distance on a levelled road.
Who does more work against the force of gravity and why?
Name the quality which is measured in kWh.
A boy weighing 350 N climbs up 30 steps, each 20 cm high in 1 minute, Calculate:
- the work done and
- power spent.
How much force is applied on a body when 150 J of work is done in displacing the body through a distance of 10 m in the direction of the force?
Work done by a force is equal to the product of ....... and ....
A coolie carrying a load on his head and moving on a frictionless horizontal platform does no work. Explain the reason why.
The world record for weight lifting was held by Sergei Didyk of the USSR. He lifted 261 kg to a height of 2.3 m in 4s; find:
(a) Weight lifted by him
(b) Work done by him
(c) Power developed by him. (g = 10m/s2)
A force of 1 kgf displaces a body by a distance of 10 cm
(i) in direction of force,
(ii) normal to the force
(iii) at an angle of 60° to the direction of the force.
Calculate the amount of work done in each case. (Take: g = 9.8 ms−2 )
For the following scenario, state whether the work done by gravity is positive, negative, or zero.
A person climbs a ladder.
