Answer :
Answer:
Therefore,
The ball strike the ground at time , t = 6 s
Step-by-step explanation:
Given:
The equation for the ball’s height, h, at time t seconds is
[tex]h=-4.9t^{2}+19.6t+58.8[/tex]
To Find:
time, t = ? (When the ball strike the ground)
Solution:
When the ball strike the ground height, h will be ZERO,
So put h = 0 in above given equation for time,
[tex]0=-4.9t^{2}+19.6t+58.8[/tex]
Which is a Quadratic Equation
Dividing throughout by - 4.9 we get
[tex]0=t^{2}-4t-12[/tex]
On Factorizing, splitting the middle term we get
[tex]t^{2}-6t+4t-12=0[/tex]
[tex]t(t-6)+2(t-6)=0\\\\(t+2)(t-6)=0\\\\t=-2\ or\ t=6[/tex]
As time cannot be negative,
t = 6 s
Therefore,
The ball strike the ground at time , t = 6 s