Advertisements
Advertisements
प्रश्न
When do we say that work is done? Write the formula for the work done by a body in moving up against gravity. Give the meaning of each symbol which occurs in it.
Advertisements
उत्तर
The necessary condition for a force to do work is: the applied force must cause a displacement along the direction of the force.
Work done can be negative, positive or zero depending upon the direction of motion and force applied.
We can calculate the work done against gravity in moving a body of mass (m) by a height (h) as, Work done in lifting a body = (Weight of body) × (Vertical distance)
So, W = m × g × h
Where,
(W) - Work done
(m) - Mass of body
(g) - Acceleration due to gravity
(h) - Height through which the body is lifted
APPEARS IN
संबंधित प्रश्न
An electron emitter must have _____________ work function and ___________ melting point.
Derive a relationship between S.I. and C.C.S. unit of work
In which of the following cases, is work being done?
(i) A man pushing a wall.
(ii) a coolie standing with a load of 12 kgf on his head.
(iii) A boy climbing up a staircase.
A boy throws a rubber ball vertically upwards. What type of work, positive or negative, is done : by the force applied by the boy?
(a) by the force applied by the boy?
(b) by the gravitational force of earth?
Determine the amount of work done when an object is displaced at an angle of 30° with respect to the direction of the applied force.
On what factors does the work done by a force depend?
A force is applied on a body of mass 20 kg moving with a velocity of 40 ms−1. The body attains a velocity of 50 ms−1 in 2 seconds. Calculate the work done by the body.
State whether work is done or not, by writing yes or no, in the following case:
A boy climbs up 20 stairs.
