B - A = (7, 8) - (-5, 8) = (7 -(-5), 8 -8) = (12, 0)
The distance is then ...
d = √(12² + 0²) = √12²
d = 12
_____
Of course, when you graph these points (actually or mentally), you can see that they are 12 units apart on the line y=8. You don't need to do any fancy calculation to discover the difference between -5 and 7.
Velocity is defined as the rate of change of position. Therefore,
So, the velocity function is
When a body reaches a vertical velocity of zero, this is the maximum height of the body and then gravity will take over and accelerate the object downward. Thus,
We know that the ball bearing reaches its maximum height 21 seconds after being launched (t = 21 s).