Answer:
8 seconds
Step-by-step explanation:
Given
h = - 5t² + 40t
When the object hits the ground then h = 0
Substitute h = 0 into the function and solve for t
- 5t² + 40t = 0 ← factor out - 5t from each term
- 5t(t - 8) = 0
Equate each factor to zero and solve for t
- 5t = 0 ⇒ t = 0
t - 8 = 0 ⇒ t = 8
t= 0 denotes the time of launch
t = 8 denotes the time it hits the ground
- Center =

- Radius =

<u>Step-by-step explanation:</u>
Here we have following equation : 
We need to find the center & radius of this circle . Let's find out:
We know that , Equation of a circle is given by :
⇒
........(1)
Here , (h,k) are the co-ordinates of center & r is the radius of circle.Collectively called as a circle with radius r and center at (h,k) . Let's frame given equation in question :
⇒ 
⇒ 
On comparing this equation with equation (1) we get :
- Center =

- Radius =

Answer:
D
Step-by-step explanation:
D
m <6+ m<8 = 180°
[ Straight/Linear Angle]