A boy of mass m with his mass centered at height H is standing in a train moving with constant acceleration a. If his legs are wide spread with a distance 2Jand he is not taking the help of any support then normal reactions at his feet are given by
A
B
m (a + g), mg
C
D
mg, mg
Text Solution
Verified by ExpertsThe correct answer is:
A
If N 1 and N 2 are the normal reactions at one foot and the other foot, then
N 1 + N 2 = mg ……….. (i)
For equilibrium,
(ma) H = dN 1 – dN 2 = d(N 1 – N 2 )
(taking moments about centre of mass)
or N 1 – N 2 = (ma) 
……….. (ii)
From (i) and (ii)
2N 1 = mg + ma 
= 
or N 1 = 
and N 2 = 
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