Question

A ball of 100 g mass is moved with 10 m/s, and decreases to 5 m/s in 5 seconds due to air friction, so force of friction due to air is​

Answer 1

$\huge\sf\pink{Answer}$

☞ Force of air is -0.1 N

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$\huge\sf\blue{Given}$

✭ Initial Velocity (u) = 10 m/s

✭ Final Velocity (v) = 5 m/s

✭ Mass (m) = 100 g = 100/1000 = 0.1 kg

✭ Time (t) = 5 sec

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$\huge\sf\gray{To \:Find}$

◈ Friction due to air?

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$\huge\sf\purple{Steps}$

So here we shall use Newton's second law of motion, that is,

$\underline{\boxed{\sf F=ma}}$

But here first we should find acceleration of the body and to find that we shall use the first equation of motion, that is,

$\underline{\boxed{\sf v = u+at}}$

Substituting the given values,

➝ $\sf v = u+at$

➝ $\sf 5=10+a\times 5$

➝ $\sf 5-10=5a$

➝ $\sf -5=5a$

➝ $\sf \dfrac{-5}{5} = a$

➝ $\sf \red{a=-1 \ m/s^2}$

So now substitute the required Values in F = ma

➳ $\sf F=ma$

➳ $\sf F=0.1\times -1$

➳ $\sf \orange{F=-0.1 \ N}$

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