the height of the rocket above ground is modelled by the quadratic function h(t)= -4t^2 + 32t, where h(t) is the height in metres, t seconds after the rocket was launched. How long will the rocket be in the air? how do you know?

so the vertex is (4,64)
the rocket is at it's maximum point in the air only after four seconds.
therefore, is it correct to say that the rocket is in the air for a total of 8 seconds since that is when it is on the ground again?

Question

the height of the rocket above ground is modelled by the quadratic function h(t)= -4t^2 + 32t, where h(t) is the height in metres, t seconds after the rocket was launched. How long will the rocket be in the air? how do you know?

so the vertex is (4,64)
the rocket is at it's maximum point in the air only after four seconds.
therefore, is it correct to say that the rocket is in the air for a total of 8 seconds since that is when it is on the ground again?

anonymous · Answer

The answer should be 4 secs

anonymous · Answer

but then the rocket is still in the air after four seconds do i not count that ?

anonymous · Answer

I am very sorry it should be 8 secs since if you put h(t) as 0 then you can find the time

anonymous · Answer

thanks @coolben77 :)