Question

find weight of half metre scale balanced at 5cm mark when weight of 10 gf if suspended at its one end​

Answer 1

PLEASE MAKE ME BRILLIANT

Let the weight of the half metre rule be x gf and it acts at the 25 cm mark (centre of gravity).

Now,

Acticlockwise moment = x×4

Clockwise moment = 20×21

In equilibrium,

Anticlockwise moment = Clockwise moment

4x=20×21

x=105 gf.

Thus, the weight of the metre rule is 105gf.

We know, one gf is the force acting on the body of mass 1 grams, thus mass of the body is 105grams.

Answer 2

Given: A half metre scale is balanced at 5 cm mark when weight of 10 gf is suspended at its one end​.

To find: The weight of half metre scale.

Solution:

• The centre of mass of a half metre scale is at 25 cm mark.
• Let x be the weight of half metre scale.
• The anticlockwise moment is found as follows.

        $Anticlockwise = x * (c - f)$

• Here, c is the point of centre of mass of the scale and f is the mark at which the scale is balanced.

        $Anticlockwise = x * (25 - 5)$  

                               $= 20 x$

• The anticlockwise moment is calculated as follows.

        $Clockwise = d * w$

• Here, w is the weight suspended at the scale's one end​ and d is the distance between the mark at which the scale is balanced and the mark at which the weight is suspended.

        $Clockwise = 5 * 10 gf$

• When in equilibrium the anticlockwise moment is equal to the clockwise moment.

        $20 x = 5 * 10$

        $x = 2.5 gf$

Therefore, the weight of half metre scale is 2.5 gf.