Answer:
The height of the object after 3 seconds is 45 feets.
Step-by-step explanation:
The height of an object thrown into the air with an initial upward velocity of 63 feet per second is given as
[tex]h(t)=-16t^2+63t[/tex]
Where, h(t) is height of the object in feet and t is the time in seconds.
We have to find the height of the object after 3 seconds. So, substitute t=3.
[tex]h(3)=-16(3)^2+63(3)[/tex]
[tex]h(3)=-16(9)+189[/tex]
[tex]h(3)=-144+189[/tex]
[tex]h(3)=45[/tex]
Therefore height of the object after 3 seconds is 45 feets.
