Question

Eighty railway wagons all of the same mass $5\times {10}^3$ $kg$ are pulled by an engine with a force of $4\times {10}^5$ $N$. The tension in the coupling between ${30}^{th}$ and ${31}^{st}$ wagon from the engine is

• A. $25\times {10}^4$ $N$
• B. $40\times {10}^4$ $N$
• C. $20\times {10}^4$ $N$
• D. $32\times {10}^4$ $N$

Answer 1

The correct option is A $25\times {10}^4$ $N$

Mass of each wagon $=5\times {10}^3$ $kg$

Force applied on the engine $=4\times {10}^5$ $N$

Total mass of $80$ wagons $=80\times 5\times {10}^3$ $kg$

$ma=4\times {10}^5$

$a=1$ $m/s^2$

So, wagon to the right side which produces tension,

$\Rightarrow T=50\times$ one wagon mass $\times a$

$\Rightarrow T=50\times 5\times {10}^3\times 1$

$\Rightarrow T=25\times {10}^4$ $N$