A rigid massless rod `AB` of length `1 m` is placed horizontally on two rigid supports at its ends as showm in figure. A weight `10 N` is hung from a point `C` at a distance `30 cm` from `A`. Find the reactions at the supports `A` and `B` respectively.
.

Options

A. 5 N, 5 N
B. 3 N, 7 N
C. 10 N, 0 N
D. 7 N, 3 N

Answer

D

Explanation

(d) `R_1 + R_2 = 10`
`Sigma tau_A = 0 rArr R_2 xx 1 - 10 xx 0.3 = 0`
`rArr R_2 = 3N, R_1 = 10 - R_2 = 10 -3 = 7 N`.