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# A basketball is thrown vertically upward in the air

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A basketball is thrown vertically upward in the air from the top of a cliff. Its height above the ground is approximated by the relation  h=  - 4t2  + 32t  + 80, where h is the height in metres above ground level and t is the time in seconds.

a) Find the zeros of the relation. [Hint: Change to factored form]

b) Find the coordinates of the vertex.

c) State the time when the basketball hits the ground

d) State the time when the basketball hits the ground

e) What is the height of the cliff? (i.e. what is the initial height of the ball?)

f) What is the height of the basketball at 8 seconds?

Mar 17, 2021

#1
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a) -4t^2 +32t  +80 = 0  divide by -4

t^2 - 8t -20 = 0

(t-10)(t+2) = 0

t = 10   t = -2

b.)     x = between the zeroes = 4

y =    -4(4^2) + 32(4) + 80 = ..........

c)   h= 0      when ball hits ground     0 = - 4t^2 + 32t + 80    sove for 't'   throw out negative value

e) put t= 0 ito the equation to find the height of the cliff = 80 m

Mar 17, 2021

#1
+1

a) -4t^2 +32t  +80 = 0  divide by -4

t^2 - 8t -20 = 0

(t-10)(t+2) = 0

t = 10   t = -2

b.)     x = between the zeroes = 4

y =    -4(4^2) + 32(4) + 80 = ..........

c)   h= 0      when ball hits ground     0 = - 4t^2 + 32t + 80    sove for 't'   throw out negative value