Question

A metal bar of 70 cm long and 4 kg in mass supported on two knife edges placed 20 cm from each end. A 6 kg load is suspended at 30 cm from on end. Find the normal reaction at the knife-edge. (assume it to be of uniform cross section and homogeneous).​

Answer 1

Answer:

Let the normal reactions from the knife edges (K1 & K2) be N1,N2

Now since the bar is in equilibrium,

N1+N2=mg

N1+N2=10×9.8N=98NAlso the system is in rotational equilibrium too.Thus, about the center of the rod, the net torque must be zero.Hence

(6×9.8)(5)+(N2)(25)=(N1)(25)⟹N1=55N

N2=43N

=43NHence normal reaction 55 N at K1 and 43 N at K2 are formed.

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I hope this helps you.......