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 :

विकल्प

• 200 J

•  800 J

• 8000 J

• 2000 J

Answer 1

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.