Q. If the acceleration due to gravity is $10\ ms^{- 2}$ and the units of length and time are changed in kilometer and hour respectively, the numerical value of the acceleration is
A) $360000$
B) $72,000$
C) $36,000$
D) $129600$
Explanation
$n_{2} = n_{1}\left\lbrack \frac{L_{1}}{L_{2}} \right\rbrack^{1}\left\lbrack \frac{T_{1}}{T_{2}} \right\rbrack^{- 2} = 10\left\lbrack \frac{m}{km} \right\rbrack^{1}\left\lbrack \frac{\sec}{hr} \right\rbrack^{- 2}$ $n_{2} = 10\left\lbrack \frac{m}{10^{3}m} \right\rbrack^{1}\left\lbrack \frac{\sec}{3600\ \sec} \right\rbrack^{- 2} = 129600$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.