Question

A rod of weight w is supported by two parallel knife edges A and B and is in equilibrium in a horizontal position. The knives are at a distance d from each other. The centre of mass of the rod is at distance x from A. The normal reaction on A is.. And on B is......
A. `(W d)/(x)`
B. `(W(d - x))/(x)`
C. `(W (d - x))/(d)`
D. `(W x)/(d)`

Answer 1

Correct Answer - C
Here, for equilibrium,
`N_(A) + N_(B) :. N_(B) = W - N_(A)`
`N_(A) = N_(B) (d - x)`
`N_(A)x = (W - N_(A)) (d - x) = W (d - x) - N_(A) (d - x)`
`N_(A) x + N_(A) (d - x) = W(d - x)`
`N_(A) = (W(d - x))/(d)`