Q123 / 150 · MHT CET 2020 (19 Oct Shift 1) · Physics

The percentage errors in measurements of mass and speed of a body are $2 \%$ and $3 \%$ respectively. What is the percentage error in kinetic energy of the body?

  • A
    $9 \%$
  • B
    $5 \%$
  • Correct answer
    C
    $8 \%$
  • D
    $0 \%$

Solution

(C) Given percentage errors in mass and velocity $=2 \%$ and $3 \%$ respectively The kinetic energy of the particle is given by $\mathrm{KE}=\frac{\mathrm{mv}^{2}}{2}$ The percentage error in kinetic energy will be $\frac{\Delta \mathrm{m}}{\mathrm{m}} \times 100+2 \frac{\Delta \mathrm{v}}{\mathrm{v}} \times 100$ $\begin{array}{l} =2+6 \\ =8 \% \end{array}$

Hence, the correct answer is option: 'C'.

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