PREVIOUSLY ASKED IN:
PSC Miscellaneous Prelims 2018
Answer
36 km/hr
Explanation
Passing a pole, tree, or standing man means the train has to cover a distance equal to its own length. Here, Distance (Train length) = 150 m and Time = 15 seconds. Speed of the train = Distance / Time = 150 / 15 = 10 meters/second. To convert the speed from m/s to km/hr, we multiply by 18/5. Therefore, Speed in km/hr = 10 × (18 / 5) = 36 km/hr.
Key Points
- > When a train passes a pole, Distance = Length of the train.
- > Speed formula: Speed = Distance / Time.
- > Speed = 150 m / 15 s = 10 m/s.
- > Conversion factor from m/s to km/hr is 18/5.
- > Conversion factor from km/hr to m/s is 5/18.
- > 10 × (18/5) = 36 km/hr.
Additional Information
Speed Conversion Matrix (m/s vs km/hr)
| Meters/Second (m/s) | Kilometers/Hour (km/hr) |
|---|---|
| 5 m/s | 18 km/hr |
| 10 m/s | 36 km/hr |
| 15 m/s | 54 km/hr |
| 20 m/s | 72 km/hr |
Memory Tips
- The 5-18 Multiplication Table: The scale of m/s moves in multiples of 5, while km/hr moves in multiples of 18. Since 10 m/s is 5 × 2, the km/hr equivalent is 18 × 2 = 36 km/hr.