Question

a boy mass 50 kg running at 5 M per second jumps onto a trolley of 20 kg travelling in the same direction at 1.5 m per second find their common velocity

Answer 1

$\textbf{\huge{Hey there!}}\\\\\textbf{\large{\underline{Details of boy,}}}\\Mass(M_1) = 50 \ kg\\Velocity \ acquired (V_1)= 5 \ m/s\\\\\textbf{\large{\underline{Details of trolley,}}}\\Mass(M_2) = 20 \ kg\\Velocity(V_2) = 1.5 \ m/s\\\\\text{Total Mass after jump }= 50+20 = 70 \ kg\\V = ?\\\\\textbf{\underline{{By Momentum conservation;}}}\\\\\boxed{\boxed{\bold{\large{MV = M_1V_1 + M_2V_2}}}}\\\implies 70 \times V = 50 \times 5 + 20 \times 1.5\\\implies 70 V = 280\\\implies V = 4 \ m/s$

$\boxed{\boxed{\textbf{\large{Common Velocity = 2 m/s}}}}}}$

$\text{\large\Math{{Hope It Helps You!}}}$