The horizontal and vertical components of the initial velocity of a football are 16 m/s and 20 m/s respectively. If there is no air resistance, how long does it take the football to reach the top of its trajectory?

t = 2 sec

Explanation:

Given that

Ui = 16 m/s

Vi = 20 m/s

As we know that at the maximum height, the y component of velocity will become zero.

We know that horizontal component of velocity will remain constant trough out the motion.

We also know that acceleration due to gravity is in downward direction.

Vf = Vi - g t

Now by putting the values

0 = 20 - 10 x t (take g = 10 m/s²)

20 = 10 t

t = 2 sec

Therefore the answer is 2 sec.