Adart gun shoots a dart with an angle of 45' above horizontal during the upward part of the trajectory the gravitational acceleration g is directed 1 upward and ts value changes with height 2 upward and its value changes with height 3 there is no accelaration 4 downward and its value is constant 5 downward and ts value changes with height

4. Downward and its value is constant

Explanation:

As this is a case of projectile motion, we use the reference frame where upward direction to be positive for , and in the same way to be negative in the downward direction. On another hand, we have that gravity is always acting this means that gravitational acceleration g is directed downward constantly over the dart not only during the upward but also during the downward part of the trajectory. And it is ruled by the following equations.

For the x-axis

For the y-axis

Where , is the initial velocity.