This is the problem from our Physics textbook :
A player throws a ball upwards with an initial speed of 29.4 m s–1. (a) Choose the x = 0 m and t = 0 s to be the location and time of the ball at its highest point, vertically downward direction to be the positive direction of x-axis, and give the signs of position, velocity and acceleration of the ball during its upward, and downward motion.
Answer is :
x > 0 (upward and downward motion); v < 0 (upward), v > 0 (downward), a > 0 throughout;
a > 0 is what is bothering me and I have done hours of searching and trying to understand.
Kindly explain all the parts of the answer. Thanks in advance.