A ball is thrown straight up in the air. For which situations are both the instantaneous velocity and the acceleration zero? a. on the way up
b. at the top of its flight path
c. on the way down
d. halfway up and halfway down
e. none of the above

e: none of the above.

Explanation:

For any object in the air, the gravitational acceleration will be always -9.8m/s^2, where the negative sign is because gravity pulls the object down.

The instantaneous velocity, as a function of time, for the case of the ball, is

V(t) = (-9.8m/s^2)*t + v0

Where v0 is the velocity at which the ball is thrown up.

The velocity will be zero when the ball is at the top of its flight pat, in that point the sign of the velocity changes, it stops being positive (so the ball stops going up) and becomes negative (so the ball starts to fall down).

Now, while the instantaneous velocity can be zero during the flight, the acceleration does not, it only will be zero when the object hits the ground. Then the only correct option will be e: none of the above.

a.   mass number from atomic number