Juan hits a baseball. The equation #h=-16t^2+120t# models the height h in feet after the ball after t seconds. How long is the ball in the air?

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Answer 1 · 2017-07-30T08:57:23

The ball is in the air for #=7.5s#

The equation is

#h(t)=-16t^2+120t#

When the ball touches the ground , #h(t)=0#

Therefore,

#-16t^2-120t=0#

#t(-16t-120)=0#

So,

#t=0# is the starting time

and

#-16t-120=0#, #=>#, #t=120/16=7.5s#