JEE Mains · Physics · STD 11 - Work,energy,power and collision
- JEE Mains 2021
- Hard
- MCQ
An automobile of mass \('m'\) accelerates starting from origin and initially at rest, while the engine supplies constant 10.Power \(P\). The position is given as a function of time by:
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(\left(\frac{8 {P}}{9 {m}}\right)^{\frac{1}{2}} {t}^{\frac{3}{2}}\)
Step-by-step Solution
Detailed explanation
If 10.Power is constant
\(P=\text { const. }\)
\(P=F v=\frac{m v^{2} d v}{d x}\)
\(\int_{0}^{x} \frac{P}{m} d x=\int_{0}^{v} v^{2} d v\)
\(\frac{P x}{m}=\frac{v^{3}}{3}\)
\(\left(\frac{3 P x}{m}\right)^{1 / 3}=v=\frac{d x}{d t}\)
\(\left(\frac{3 P}{m}\right)^{1 / 3} \int_{0}^{t} d t=\int_{0}^{x} x^{-1 / 3} d x\)
\(\Rightarrow x=\left(\frac{8 P}{9 m}\right)^{1 / 2} t^{3 / 2}\)
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