Question

Refer to two 1 kg masses moving toward each other, one mass with velocity $v_1$= 10 m/s, the other with velocity $v_2$= 20 m/s. What is the total energy of the system?

• A. $50J$
• B. $150J$
• C. $200J$
• D. $250J$
• E. $400J$

Answer 1

The correct option is D $250J$

Given : $v_1=10m/s$ $m_1=1kg$ $v_2=20m/s$ $m_2=1kg$

Total kinetic energy of the system $K.E=\frac{1}{2}{m}_1{v}_1^2+\frac{1}{2}{m}_2{v}_2^2$

$\therefore$ $K.E=\frac{1}{2}\times 1\times (10{)}^2+\frac{1}{2}\times 1\times (20{)}^{2}50+200=250J$