Question

answer this question please​

Answer 1

❍ Question :-

• A car completes its journey in a straight line in three qual parts with speeds V₁, V₂ and V₃ respectively. The average speed V is given by

★ Option :-

(a) V₁ + V₂ + V₃ / 3

(b) √V₁ V₂ V₃

(c) 1/V = 1/V₁ + 1/V₂ + 1/V₃

(d) 3/V = 1/V₁ + 1/V₂ + 1/V₃

❍ Given :-

• d = V₁, t₁
• t₁ = d/ V₁
• t₂ = d/V₂
• t₃ = d/V₃

❍ To find :-

• Find the average speed V is

❍ Let's Do.... !!

$\: \: \: \purple{: \implies}\underline{\underline{ \sf \: V_{(avg)} = \dfrac{3d}{t_{1} + t₂ + t₃}}}$

$\: \: \: \: \: \: \: \: \: \underline{\underline{ \sf \: V_{(avg)} = \dfrac{3 \cancel{d}}{ \dfrac{ \cancel{d}}{V_{1}} + \dfrac{ \cancel{d}}{V₂} + \dfrac{ \cancel{d}}{V₃}}}}$

$\: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \purple{:\implies} \underline{\underline{\sf \dfrac{3}{V_{1}, V₂, V₃}}}$

$\: \: \: \: \: \: \: \: \: \purple{: \implies} \underline{\underline{\sf \: \dfrac{1}{V}= \dfrac{\frac{1}{V_{1}}+ \frac{1}{V₂} + \frac{1}{V₃}}{3}}}$

Final answer :-

$\: \: \: \: \: ● \: \underline{\boxed{\sf \frac{3}{V} = \frac{1}{V_{1}}+ \frac{1}{V₂} + \frac{1}{V₃}}}$

• Hence, Option (d) 3/V = 1/V₁ + 1/V₂ + 1/V₃ is correct answer.