A non uniform meter rule pivoted at the 30cm mark .It is balanced horizontally by a force W placed at the 20cm mark and 0.4N force placed at the 70cm mark . Determine the weight W

To determine the weight W, we can use the principle of moments. The total clockwise moments about the pivot point must be equal to the total anticlockwise moments.

Clockwise moments = Anticlockwise moments
(W x 10cm) + (0.4N x 30cm) = (W x 10cm) + (0.4N x 40cm)

10W + 12 = 4W + 16
10W - 4W = 16 - 12
6W = 4
W = 4/6
W = 0.67N

Therefore, the weight W is 0.67N.