#### Answer

A) The average velocity is 0
B) The average speed is 10m/s

#### Work Step by Step

A) The formula for average velocity is:
Velocity = $\frac{\Delta displacement}{Time}$
Since the track is circular, one lap makes the race car return to its starting position. This means that the displacement is 0, making the average velocity equal to 0.
B) The average speed is:
Speed = $\frac{Distance}{Time}$
The Total distance traveled is 500m, and the total time is 50s. So, placing these values in the equation makes the speed equal to 10m/s.