That means the angle is between 90 and 180 degrees. Not bad eh? Lastly, you’re going for an acute angle. That’s one that’s less than 90 degrees. Bad luck. So each time you cut these you are ...

On the right side, P moves with increasing/decreasing speed. When the speed is increasing, the angle between v and a is less than 90 degrees, and greater than 90 degrees with the speed is decreasing.