Question

a ball is vertically projected with an initial velocity of 39.2m/s find (a)maximum height (b)and time of descent​

Answer 1

Explanation:

Initial velocity = 39.2m/s

acceleration due to gravity

= 9.8m/s²

Since the ball is projected upwards so at one point of time and at a specific height, it's motion will stop and it will start coming down.

When the ball is projected upwards,

Final velocity at a specific height = 0m/s

From the formula,

v = u + at

0 = 39.2 - 9.8t

t = 4s

Time of descent = 4s

From formula,

S = ut + 1/2at²

S = 39.2×4 - 1/2×9.8×4×4

S = 156.8 - 78.4

S = 78.4 m

Maximum height reached = 78.4m