Question

If the acceleration due to gravity is $10m{s}^{-1}$ and the units of length and time are changed in kilometer and hour respectively, the numerical value of accelerations is :

• A. $360000$
• B. $72000$
• C. $36000$
• D. $129600$

Answer 1

The correct option is D $129600$

The acceleration is given as,

$1m{s}^{-2}=\frac{1m}{1s\times 1s}$

$1m{s}^{-2}=\frac{1\times {10}^{-3}km}{\frac{1}{3600}hr\times \frac{1}{3600}hr}$

$1m{s}^{-2}=12960kmh{r}^{-2}$

The acceleration due to gravity is given as,

$10m{s}^{-2}=129600kmh{r}^{-2}$

Thus, the numerical value of acceleration is $129600$.