Question

$80$ railway wagons all of 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

Answer: (A)

Railway waygons to be pulled = 80 - 30 = 50
$\therefore m=50\times 5\times 10^{3}kg$
$a=\frac{\textit{F}}{\text{80 } \textit{M}}=\frac{4 \times \text{10}^{5}}{\text{80} \times 5 \times \text{10}^{3}}$
$\Rightarrow \text{F}_{\text{30}} = \text{50} \times 5 \times \text{10}^{3} \times \frac{4 \times \text{10}^{5}}{\text{80} \times 5 \times \text{10}^{3}}$ $=25\times 10^{4}N$