The horizontal and vertical components of the initial velocity of a football are 16 m/s and 20 m/s respectively. How long does it take for the football to rise to the highest point of its trajectory?
A) 1.0 s
B) 2.0 s
C) 3.0 s
D) 4.0 s
E) 5.0 s

Question

Quizplus · Accepted Answer

To find the time taken for the football to rise to its highest point, we need to use the fact that the vertical velocity at the highest point is 0 m/s. We know that the initial vertical velocity is 20 m/s, and due to gravity, the vertical velocity decreases at a rate of 9.8 m/s^2. Therefore, we can use the following kinematic equation to find the time taken:

vf = vi + at

where 
vf = final velocity (0 m/s) 
vi = initial velocity (20 m/s) 
a = acceleration (-9.8 m/s^2) 
t = time

0 = 20 - 9.8t

9.8t = 20

t = 20/9.8 ≈ 2.04 s

Therefore, the football takes about 2.0 seconds to rise to the highest point of its trajectory. The best answer choice is B.

The Horizontal and Vertical Components of the Initial Velocity of a Football