Which of the following speeds is the least?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 50 meter/minute
Speeds can be compared only when they are in the same unit. Each speed is turned into metres per minute (1 km = 1000 m, 1 hour = 60 minutes, 1 minute = 60 seconds):
50 m/s \(=50\times60=3000\) m/min
50 m/min, as given
70 km/h \(\displaystyle=\frac{70000}{60}\approx1167\) m/min
5 km/min \(=5000\) m/min
The smallest of these is 50 m/min, slower than a person walking.