Question

The momentum of a body os $20,000$ dyne-sec. Its KE is $200erg$, the mass of the body is

• A. $100kg$
• B. $200kg$
• C. $2000kg$
• D. $1000kg$

Answer 1

The correct option is D $1000kg$

In CGS unit ,unit of mass will be given in grams.

$K.E=\frac{1}{2}m{v}^2$

$=\frac{1}{2m}\left(m^2{v}^2\right)=\frac{1}{2m}(momentum{)}^2$

$200=\frac{1}{2m}(20000{)}^2$

$m=\frac{1}{400}\times (20000{)}^2=(1000{)}^{2}g$

$m={10}^{6}g={10}^{3}kg=1000kg$