Question

What will be the unit of time in that system in which the unit of length is metre, unit of mass is kg and unit of force is kg wt?

• A. $(9.8)^2\, s$
• B. $9.8\,s$
• C. $\sqrt{9.8}\,s$
• D. $\frac{1}{\sqrt{9.8}}\,s$

Answer 1

Answer: (D)

$\frac{1}{\sqrt{9.8}}\,s$

Answer 2

As $\left[F\right] = \left[MLT^{-2}\right]$ $\therefore\quad T^{2} = \frac{ML}{F} = \frac{1\,kg\times1\,m}{1\,kg\,wt} =\frac{1\,kg\times 1\,m}{9.8\,N}$ $\left(\because 1\,kg \,wt = 9.8\,N\right)$ or $= \frac{1}{\sqrt{9.8}}\,s$