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Complete Question:
The height of a diver jumping from a diving platform is about [tex]h(t)= 16t^2 +11t+10[/tex], where h is the height of the diver in feet above the water and t is the time measured in seconds, when diving from a platform about 34.3 feet above the water with an upward initial velocity of 11 ft/sec.. After how many seconds is the diver's height above the water 15 feet?
Answer:
0.3125 seconds
Step-by-step explanation:
Given
[tex]h(t)= 16t^2 +11t+10[/tex]
Required
Time when the diver is above 15ft
This implies that h(t) = 15
So, we have:
[tex]15= 16t^2 +11t+10[/tex]
Collect Like Terms
[tex]0= 16t^2 +11t+10 - 15[/tex]
[tex]0= 16t^2 +11t-5[/tex]
[tex]16t^2 +11t-5=0[/tex]
Expand:
[tex]16t^2 + 16t - 5t - 5 = 0[/tex]
Factorize:
[tex]16t(t + 1) - 5(t + 1) = 0[/tex]
[tex](16t - 5)(t + 1)=0[/tex]
Split
[tex]16t - 5 = 0[/tex] or [tex]t + 1 = 0[/tex]
[tex]16t = 5[/tex] or [tex]t + 1 = 0[/tex]
Solve for t
[tex]t = 5/16[/tex] or [tex]t = -1[/tex]
[tex]t = 0.3125[/tex] or [tex]t = -1[/tex]
But time can't be negative. So:
[tex]t = 0.3125[/tex]
Hence, it will take the diver 0.3125 seconds to be at a height above 15 feet
It will take t = 0.3125 seconds is the diver's height above the water 15 feet.
Given ,
The height of a diver jumping from a diving platform is h
h(t) = [tex]-16t^{2} + vt + 10[/tex]
The diver's height above the water 15 feet
Velocity = v = 11 ft per second
We have to find, t seconds is the diver's height above the water 15 feet.
According to the question,
[tex]h(t) = -16t^{2} +vt+10[/tex]
Where v = 11, h(t) = 15
15 = -16[tex]t^{2}[/tex] + 11t + 10
15 - 10 = [tex]-16t^{2} + 11t[/tex]
5 = [tex]-16t^{2} +11t[/tex]
[tex]16t^{2} -11t +5= 0[/tex]
[tex]16t^{2} -16t - 5t + 5 = 0[/tex]
16t ( t - 1 ) - 5 ( t + 1 ) = 0
(16t - 5 ) ( t + 1 ) = 0
16t - 5 = 0
16t = 5
t = [tex]\frac{5}{16}[/tex]
t = 0.3125
And t + 1 = 0
t = -1
Time can not be negative so we can't take t = -1 .
So, The required value of time is t = 0.3125
Hence, it will take t= 0.3125 seconds is the diver's height above the water 15 feet.
For the more information about Equation of motion click the link given below.
https://brainly.com/question/13514745