Question

A uniform metal bar 90 cm long and 6 kg in mass is supported on two knife edge placed 20 cm from each end. A 10 kg weight is suspended at 40 cm
From one end. The reactions at the knife edges are (g = 10 m/s?).
90 N. 70 N
80 N, 80 N
0 60 N 100 N
75 N 85 N​

Answer 1

Answer:

90N.70N.

Explanation:

Hint: At equilibrium ΣF = 0, Σ = 0

Sol.: RA + RB = w + w1

= 60 + 100

RA + RB = 160 N

Take moment about A

A = 100 × 0.2 + 60 × 0.25 – RB × 0.5

RB = 70 N

RA = 160 – 70N

=90N