- #1

karush

Gold Member

MHB

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- 5

An object is propelled vertically upward with an initial velocity of 20 meters per second.

The distance s (in meters) of the object from the ground after t seconds is

$s=-4.9t^2+20t$

(a) When will the object be 15 meters above the ground?

$15=-4.9t^2+20 \implies -4.9t^2 =-5$

ok there is no term b so decided not to use quadratic formula

so far...:unsure:

$49t^2=50$

(b) When will it strike the ground?

(c) Will the object reach a height of 100 meters