Final answer:
To convert the semi-truck's velocity from 38 m/s to km/h, we multiply by the conversion factor 3.6, resulting in a speed of 136.8 km/h. The correct answer to the student's question is (a) 136.8 km/h.
Step-by-step explanation:
To convert the semi-truck's velocity from meters per second (m/s) to kilometers per hour (km/h), we use the conversion factor that 1 m/s is equal to 3.6 km/h. Therefore, if the semi-truck is traveling at a velocity of v=38 m/s, the calculation to convert this to km/h is as follows:
Speed in km/h = speed in m/s × conversion factor
Speed in km/h = 38 m/s × 3.6 km/h per m/s
Speed in km/h = 136.8 km/h
Therefore, the correct answer to the student's question is (a) 136.8 km/h.