Selina Solutions Class 9 Physics Solutions for Exercise 5B in Chapter 5 - Chapter 5 Upthrust In Fluids Archimedes Principle And Floatation

Question 30 Exercise 5B

A body weighs 20gf in air and 18 gf in water. Calculate relative density of the material of

the body

Answer:

Weight of the body in the air, W1 = 20gf

Weight of the body in water, W2 = 18gf

We know that, R.D of solid =

W1/W1−W2 x relative density of water

$\begin{aligned} &=\frac{20}{20-18} \times 1\\ &\text { [R.D. of water is } 1]\\ &=10 \end{aligned}$

Video transcript

hello everyone welcome to lido this is priya and here we have a question to find out the density of the material let us look into the question a body weighs 2 gf in air and 18 gf in water calculate relative density of the material of the body from this question we know the weight of the body which is in air it is 20 gt 20 g gf and in water it is 18 gf and we need to find out the relative density of the material as we know the w 1 from this question is 20 g f and w 2 equal to 18 g f and we know the relative density of water rt of water is one and we know a formula to find out the relative density of solid it is w1 by w1 minus w2 into rd of water substituting these values 20 by 20 minus 18 into 1 when we simplify this we'll get 10 as an answer so the relative density of this material is 10. hope you understand this video if you like my video please subscribe to our leader channel and if you have any doubt you can keep a message in comment box thank you

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Exercises

Exercise 5A

Exercise 5B

Exercise 5C

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