Advertisements
Advertisements
Question
A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 m s−2, the work by her after climbing 2 m will be :
Options
200 J
800 J
8000 J
2000 J
Advertisements
Solution
Weight of the girl (W) = 400 N
Vertical height (h) = 2 m
Acceleration due to gravity (g) = 10 m/s2
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)
So,
Work done in lifting a body
= (400)(2) J
= 800 J
Therefore, the answer is:
(b) 800 J.
APPEARS IN
RELATED QUESTIONS
State two factors on which the work done on a body depends.
If the work done by a force in moving an object through a distance of 20 cm is 24.2 J, what is the magnitude of the force?
State the conditions of equilibrium for a rigid body.
A man climbs a slope and another walks same distance on level road. Which of the two expends more energy and why?
A coolie is pushing a box weighing 1500 N up an inclined plane 7.5 m long on to a platform, 2.5 m above the ground.
(i) Calculate the mechanical advantage of the inclined plane. (ii) Calculate the effort applied by the coolie.
(iii) In actual practice, the coolie needs to apply more effort than what is calculated. Give one reason why you think the coolie needs to apply more effort.
Who is the odd one out?
Work done by this force at any instant is ______.
