Final answer:
The average speed of the car is 20 m/s.
Step-by-step explanation:
To find the average speed of a car that covers half the distance with a speed of 20 m/s and the other half with a speed of 30 m/s, we can use the formula for average speed, which is the total distance divided by the total time taken. Since the distance covered is the same for both speeds, we can assume the total distance is 1 unit.
To find the total time taken, we can divide the distance by the speed for each half of the distance. The first half is covered at 20 m/s, so the time taken is 1/2 divided by 20 m/s, which is 1/40 s. The second half is covered at 30 m/s, so the time taken is also 1/40 s.
Adding up the two-time intervals, we get 1/40 s + 1/40 s = 1/20 s.
Finally, we can use the formula for average speed:
Average speed = total distance / total time = 1 unit / (1/20 s) = 20 m/s.