Final answer:
To find the fastest speed, each option is converted to meters per second. The fastest speed is 4.2 x 10^-2 km/s, which equals approximately 42 m/s. The Correct Answer is option.D.
Step-by-step explanation:
The question asks to compare various speeds presented in different units to find out which one is the fastest. To accurately compare the speeds, we must convert all of them to the same unit, which is meters per second (m/s), since this is the SI unit for speed.
- 1.4 x 10^5 m/h = (1.4 x 10^5 m/h) / (3600 s/h) ≈ 38.89 m/s
- 1.4 x 10^2 km/h = (1.4 x 10^2 km/h) x (1000 m/km) / (3600 s/h) ≈ 38.89 m/s
- 40 m/s = 40 m/s (already in m/s)
- 4.2 x 10^-2 km/s = (4.2 x 10^-2 km/s) x (1000 m/km) ≈ 42 m/s
- 4.0 x 10^3 cm/s = (4.0 x 10^3 cm/s) / (100 cm/m) = 40 m/s
Comparing these values, we see that 4.2 x 10^-2 km/s is the fastest speed when converted to meters per second. The Correct Answer is option.D.