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3 years ago

“The height of an arrow” NEED HELP WITH THIS QUESTION ASAP!

Mathematics

1 answer:

goldenfox [79]3 years ago

7 0

Answer:

a) t = 0.54 seconds

b) t = 8 seconds

Step-by-step explanation:

Given in the question the equation

h = 40t - 5t²

<em> where h is height in meters</em>

<em> t is time in seconds</em>

<em />

Time it took to reach 20 meters

20 = 40t - 5t²

-5t² + 40t - 20 = 0

by using quadratic formula for factorisation

t = 0.54 (upward motion)

t = 7.46 (downward motion)

b) Time it took to reach the ground

at ground h = 0

So,

0 = 40t - 5t²

t(40 - 5t ) = 0

t = 0 (at starting point)

40 -5t = 0

5t = 40

t = 40 /5

t = 8 seconds

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