Abullet is fired straight up from a gun with a
muzzle velocity of 152 m/s.
neglecting air resistance. what will be its
displacement after 6.9s?

815.51 m

Explanation:

This situation is related to projectile motion or parabolic motion, in which the initial velocity of the bullet has only y-component, since it was fired straight up. In addition, we are dealing with constant acceleration (due gravity), therefore the following equations will be useful to solve this problem:

(1)

(2)

Where:

is the final velocity of the bullet

is the initial velocity of the bullet

is the acceleration due gravity, always directed downwards

is the time

is the vertical position of the bullet at

Let's begin by finding from (1):

(3)

(4)

Now we have to substitute (4) in (2):

(5)

Isolating :

This is the displacement  of the bullet after 6.9 s