ICSE Class 10 Physics Question 16 of 20

Force — Question 18

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Question 18

A uniform half metre rule can be balanced at the 29.0 cm mark when a mass 20g is hung from its one end.

(a) Draw a diagram of the arrangement.

(b) Find the mass of the half metre rule.

(c) In which direction would the balancing point shift if 20g mass is shifted inside from its one end?

Answer
Uniform half metre rule balanced at 29.0 cm mark. Force, Concise Physics Class 10 Solutions.

(b) Suppose, if the mass of the meter rule be M.

Given, uniform meter rule, so weight (Mg) will act at 25 cm.

Mg produces anticlockwise moment about point o.

Now, in order to balance the 20g weight is tied at 50cm point and it acts in the clockwise direction.

As we know, the principle of moments states that

Anticlockwise moment = Clockwise moment

Mg(2925)=0.02g(5029)M=21×0.024=0.105kg=105gMg(29 - 25) = 0.02 g (50-29) \\[0.5em] M = \dfrac{21\times 0.02}{4} \\[0.5em] = 0.105 kg \\[0.5em] = 105g

The weight of half the meter rule is 105 g.

(c) The balancing point will shift towards the 25 cm mark.