Question

A car of mass $M$ is tied to one end of a massless string of length $10m$. The other end of the rope is in the hands of a man of mass $M$, the entire system is on a smooth horizontal surface. The man is at $x=0$ and the cart at $x=10m$. If the man pulls the cart by a rope, the man and the cart will meet at the point

• A. $x=0$
• B. $x=5m$
• C. $x=10m$
• D. $Theywillnevermeet$

Answer 1

Answer: (B)

$x=5m$

If a man is pulling a cart then the force exerted on a car is in same direction and from the newton's third law the opposite force will act on man due to car.

so the Net external force will be zero
therefore net acceleration would be zero.

but the center of mass will remain the same. so they meet at C.O.M

From the formula of C.O.M $y_{com}=\frac{M_{man}\times 0+M_{car}\times 10}{2}$=$5m$