Advertisements
Advertisements
प्रश्न
A boy of mass 40 kg runs up a height of 30 steps, each 20 cm high. Find:
(i) The force of gravity acting on the boy.
(ii) The work done by the boy against gravity. (Take g = 9.8 ms−2)
Advertisements
उत्तर
Given : m = 40 kg, g = 9.8 ms−2
Distance moved, d = 30 × 20 cm = 600 cm = 6 m.
(i) The force of gravity, F = mg = 40 × 9.8 = 392 N.
(ii) The work done by the boy, W = F × d = 392 × 6 = 2352 J.
संबंधित प्रश्न
A uniform half meter rule balances horizontally on a knife-edge at 29 cm mark when a weight of 20 gf is suspended from one end
1) Draw a diagram of the arrangement
2) What is the weight of the half meter rule?
Explain the motion of a planet around the Sun in a circular path.
Where is the centre of gravity of a uniform ring situated?
Explain how you will determine experimentally the position of the centre of gravity for a triangular lamina (or a triangular piece of cardboard).
Give scientific reason for the following:
It is easier to push a boy standing on one leg than on both legs.
What is Gravitational force? Give gravitational units of force.
Explain why Standing passengers are not allowed on the upper deck of a double-decker bus.
If mean radius of earth is R, its angular velocity is ro and the acceleration due to gravity at the surface of the earth is g, then the cube of the radius of the orbit of satellite will be ____________.
A metal sphere is hanging from the ceiling of a vehicle. If the vehicle is moving along the horizontal road with uniform acceleration 'a' then the suspended thread of the sphere gets inclined to the vertical at an angle 'θ'. The value of acceleration 'a' is (g = acceleration due to gravity) ______.
