A bullet fired vertically from upward from a gun held 2.0m above the ground reaches its maximum height in 4.0s. calculate its initial velocity. [g = 10ms‾²]

A. 10 ms‾¹
B. 8 ms‾¹
C. 40 ms‾¹
D. 20 ms‾¹

Correct Answer:

Option C – 40 ms‾¹

Explanation

At maximum height, the final velocity, v = 0
thus from v = u + at
0 = u – at
∴ U = at = 10 x 4 = 40 mls