Advertisements
Advertisements
प्रश्न
Why is less effort needed to lift a load over an inclined plane as compared to lifting the load directly?
उत्तर
Less effort is required because for a given height ‘h’ as longer is the length ‘l’ of the inclined plane, smaller is the angle of inclination, therefore, greater is the mechanical advantage, so lesser will be the effort required. As we know
Mechanical Advantage = l/h.
APPEARS IN
संबंधित प्रश्न
State two factors on which the work done on a body depends.
When is work said to be done by a force?
A water pump raises 50 litres of water through a height of 25 m in 5 s. Calculate the power of the pump required.
(Take g = 10 N kg-1 and density of water = 1000 kg m-3)
Explain degradation of energy by taking two examples of your daily life.
In which of the following case the work done by a force will be maximum : when the angle between the direction of force and direction of motion is 0° or 90°?
Give two examples of couple action in our daily life.
Is the motion of moon around the earth in circular path an accelerated motion?
Complete the following sentences:
1 H.P. = ........ W.
(a) Define power and name its unit.
(b) A girl weighting 50 kg climbs up 60 steps each of 20 cm height in 5 minutes. Calculate the power developed.
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]
A girl of mass 40 kg runs a height of 80 stairs, each 25 cm high with a load of 20 kg on her head in 25 sec. If g is 10 m/s2, find:
(i) Gravitational force acting on the girl.
(ii) Work done by her.
(iii) Useful work done by her.
(iv) Her power in watt.
A is a push or a pull ______.
Force acting on a particle moving in a straight line varies with the velocity of the particle v as F = `K/v`, where K is a constant. The work done by this force in time t is
