Question

Force acting on a particle is $5N$. If the units of length and time are doubled and unit of mass is halved, then numerical value of the force in the new system will be

• A. $5$
• B. $1/20$
• C. $20$
• D. $1/5$

Answer 1

Answer: (C)

$n_2=n_1{\left(\frac{M_1}{M_2}\right)}^{{}^1}{\left(\frac{L_1}{L_2}\right)}^{{}^1}{\left(\frac{T_1}{T_2}\right)}^{{}^{-2}}$
$=5\left(\frac{M_1}{M_1/2}\right)\left(\frac{L_1}{2L_1}\right){\left(\frac{T_1}{2T_1}\right)}^{{}^{-2}}$
$=20$