To Find The Mass Of A Given Body Using A Metre Scale By Principle Of Moments - Practice Questions & MCQ

Aim-
To determine mass of a given body using a metre scale by principle of moments.

Apparatus-
A metre scale, a broad heavy wedge with sharp edge, a weight box, a body of unknown mass.

Theory -

If m and M be the mass of the body and mass of the weight used and a and A be the distances of their loops from wedge. Then, power (mass) arm =a, weight arm =A
From principle of moments m.g.a=M.g.A

$
m=M \frac{A}{a}
$

$\mathrm{m}=$ mass of body
$\mathrm{M}=$ mass of weight
$A=$ distance from wedge
Calculation
Mean mass, $\quad m=\frac{m_1+m_2+m_3}{3} \mathrm{~g}=\ldots \mathrm{g}$
It will be found that $M_1=M_2=M_3=m$ in all cases.

Procedure:
1. Arrange the meter scale in a horizontal position by supporting it at 50 cm mark at the sharp edge of the broad heavy wedge.
2. Take a loop thread.
3. Suspended the given body whose mass is to be determined by the loop thread at a fixed mark on the left of the wedge.
4. Suspended a paper pan on the right side of the wedge.
5. Put some known weight in the pan.

Result
The unknown mass of the body, $\mathrm{m}=\ldots \mathrm{g}$.

Precautons -

1. The wedge should be broad and heavy with sharp edge.
2. Metre scale should have uniform mass distribution.
3. Threads used for loops should be thin, light and strong,