$A$ non-uniform bar of weight $W$ is suspended at rest by two strings of negligible weight as shown in the figure. The angles made by the strings with the vertical are $36.9^{\circ}$ and $53.1^{\circ}$ respectively. The bar is $2 \; m$ long. Calculate the distance $d$ of the centre of gravity of the bar from its left end.

Vedclass pdf generator app on play store
Vedclass iOS app on app store
(N/A) The free body diagram of the bar is shown in the figure.
Length of the bar,$l = 2 \; m$.
$T_1$ and $T_2$ are the tensions in the left and right strings respectively.
For translational equilibrium in the horizontal direction:
$T_1 \sin 36.9^{\circ} = T_2 \sin 53.1^{\circ}$
$\frac{T_1}{T_2} = \frac{\sin 53.1^{\circ}}{\sin 36.9^{\circ}} = \frac{0.800}{0.600} = \frac{4}{3}$
$\Rightarrow T_1 = \frac{4}{3} T_2$
For rotational equilibrium,taking the torque about the centre of gravity:
$T_1 \cos 36.9^{\circ} \times d = T_2 \cos 53.1^{\circ} \times (2 - d)$
Substituting $T_1 = \frac{4}{3} T_2$:
$(\frac{4}{3} T_2) \times 0.800 \times d = T_2 \times 0.600 \times (2 - d)$
$\frac{3.2}{3} d = 1.2 - 0.6 d$
$1.067 d + 0.6 d = 1.2$
$1.667 d = 1.2$
$d = \frac{1.2}{1.667} \approx 0.72 \; m$.
Thus,the centre of gravity of the bar lies $0.72 \; m$ from its left end.

Explore More

Similar Questions

$A$ rod of weight $W$ is supported by two parallel knife edges $A$ and $B$ and is in equilibrium in a horizontal position. The knives are at a distance $d$ from each other. The centre of mass of the rod is at distance $x$ from $A.$ The normal reaction on $A$ is

Find the value of $T_1$ (in $N$),if the system is in equilibrium and the mass of the rod is $10 \ kg$ and its length is $10 \ m$. $[g = 10 \ m/s^2]$ (in $N$)

$A$ right triangular plate $ABC$ of mass $m$ is free to rotate in the vertical plane about a fixed horizontal axis through $A$. It is supported by a string at $B$ such that the side $AB$ is horizontal. The reaction at the support $A$ is:

Difficult
View Solution

$A$ horizontal beam is pivoted at $O$ as shown in the figure. Find the mass $m$ to make the scale straight in $kg$.

Persons $A$ and $B$ are standing on the opposite sides of a $3.5 \,m$ wide water stream which they wish to cross. Each one of them has a rigid wooden plank whose mass can be neglected. However,each plank is only slightly longer than $3 \,m$. So,they decide to arrange them together as shown in the figure. With $B$ (mass $17 \,kg$) standing on one end of the plank,the maximum mass of $A$,who can walk over the plank is close to ............ $kg$.

Vedclass Products

For Students

Vedclass Test Series

Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.

Start Free Trial
For Teachers

Exam Paper Generator

Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.

Try Free
For Institutes

Online Exam Module

Live online exams with unlimited students, 360° analytics & white-label branding.

See Demo