Question

A uniform massless rod of length 4 m is to be balanced about a point 1.25 m from one ned for which a load of 18 kgf is suspended at a point 0.6 m from the support on the shorter arm and a weight W at distance 2.5 m from the support on the longer arm. i) Find W ii) If W=5 kgf, find its position to balance the rod. iii) Name the class of lever to which to which it belongs from

Answer 1

SoluTion :-

$\fbox {Total length of rod = 4 m = 400 cm }$

(i) 18 kgf load is placed at 60 cm from the support.

W kgf weight is placed at 250 cm from the support.

By the principle of moments

18 x 60 = W x 250

W = 4.32 kgf

$\rule {190}{1}$

(ii) Given W = 5 kgf

18 kgf load is placed at 60 cm from the support.

Let 5 kgf of weight is placed at d cm from the support.

By the principle of moments

18 x 60 = 5 x d

d = 216 cm from the support on the longer arm

$\rule {190}{1}$

(iii) It belongs to Class I lever.