Question

Two girls of equal mass m jump off from the border line of a stationery carriage of mass M with same horizontal velocity u relative to the carnage. Neglecting the effect of friction

• A. They will impart greater velocity to the carriage by jumping of simultaneously.
• B. They will impart greater velocity to the carriage by jumping one after the other.
• C. They will impart greater velocity to the carriage in whatever manner they jump off.
• D. Insufficient data to reply.

Answer 1

Answer: (B)

They will impart greater velocity to the carriage by jumping one after the other.

Answer 2

Which boys jump one by one total velocity of the system will be more. (because from conservation of momentum, velocity of car in this case will be)

U_car = u $\left( \frac { 1 } { M + 2 m } + \frac { 1 } { M + m } \right)$

Instead of mu $\left( \frac { 1 } { M + 2 m } + \frac { 1 } { M + 2 m } \right)$

When they jump simultaneously.