Question

A train is moving at a constant speed of \( 54 \, \text{km/h} \). What is the speed of the train in \( \text{m/s} \)?

• A. \( 5 \, \text{m/s}^{-1} \)
• B. \( 15 \, \text{m/s}^{-1} \)
• C. \( 25 \, \text{m/s}^{-1} \)
• D. \( 35 \, \text{m/s}^{-1} \)

Hint:

To convert from \( \text{km/h} \) to \( \text{m/s} \), multiply by \( \frac{5}{18} \). This will give you the equivalent speed in meters per second.

Answer 1

The Correct Option is B

To convert the speed from \( \text{km/h} \) to \( \text{m/s} \), we use the following relation: \[ 1 \, \text{km/h} = \frac{1000 \, \text{m}}{3600 \, \text{s}} = \frac{5}{18} \, \text{m/s}. \] Convert \( 54 \, \text{km/h} \) to \( \text{m/s} \).
Now, to convert the speed of the train from kilometers per hour to meters per second, we multiply the speed in \( \text{km/h} \) by \( \frac{5}{18} \): \[ \text{Speed in m/s} = 54 \, \text{km/h} \times \frac{5}{18}. \] \[ \text{Speed in m/s} = \frac{54 \times 5}{18} = 15 \, \text{m/s}. \] Thus, the speed of the train in \( \text{m/s} \) is \( 15 \, \text{m/s} \).