The height of a projectile launched upward at a speed of 32 feet/ second from a height of 128 feet is given by the function h(t)=-16t^2+32t+128. How long will it take the projectile to hit the ground?

Respuesta :

Answer:

8.51 seconds

Step-by-step explanation:

Time to reach maximum height

=( Usin90)/2g

= 32/2*9.81

= 32/19.62

= 1.63 s

Max height = U²Sin²tita/g

= 32²/9.81

= 1024/9.81

= 104.38ft

Total height=104.38 + 128= 232.38

Time to fall back to the ground using the formula

h = ut+(1/2)gt²

U= 0

H= 232.38

g = 9.81

(232.38 *2 )/9.81= t²

47.376= t²

t = 6.88 s

Total time taken to hit ground

= 6.88 + 1.63

= 8.51 seconds

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