Question

The percentage errors in the measurement of mass and speed are 2% and 3% respectively. The error, in kinetic energy obtained by measuring mass and speed, will be:

• A. 12%
• B. 10%
• C. 8%
• D. 2%

Answer 1

The correct option is C 8%

Percentage error is mass $(\frac{\Delta m}{m}\times 100)=2$% and percentage error in speed $(\frac{\Delta v}{v}\times 100)=3$%.
Kinetic energy $E=\frac{1}{2}m{v}^2$
$\therefore \frac{\Delta E}{E}\times 100=\frac{\Delta m}{m}\times 100+2\frac{\Delta V}{V}\times 100$ $=2+2\left(3\right)=8$%