Answer:
A.607m/s | B.1.834Mach (speed of sound)
Explanation:
The plane's speed starts out at 145m/s, meaning after we calculate how many m/s it has accelerated, we must add that to the total.
If it accelerates for 20 seconds at a rate of 23.1m/s^2, this means that it accelerates 23.1m/s/s, or in words it gains 23.1 m/s every second. So, to calculate the gain in speed we simply multiply this by the duration of 20 seconds and get 462 m/s. Now, we add this to 145m/s, and get an end velocity of 607m/s.
For the plane's speed in terms of speed of sound, we divide 607m/s by the speed of sound, or 331m/s, and get ~1.834 Mach(speed of sound)
