John is traveling north at 20 meters/second and his friend betty is traveling south at 20 meters/second. if north is the positive direction, what are john and betty's speeds? a. -20 meters/second, 20 meters/second b. 20 meters/second, 20 meters/second c. -20 meters/second, -20 meters/second d. 0 meters/second, 40 meters/second

B. 20 meters/second, 20 meters/second

Explanation:

Velocity of John = 20 meters/second north = +20 meters/second

Velocity of Betty =  20 meters/second south = -20 meters/second

If north is considered as positive then south will be negative.

So, the velocity of John will be +20 meters/second and velocity of Betty will be -20 meters/second.

But, the question is about their speeds and not velocity. The signs represent the directions. Speed does not show direction.

So, speed of John and Betty is 20 meters/second.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.