Question

A rocket is fired upward from ground level with an initial velocity of 480km/hr. after t seconds its distance above the ground level is given by 480t_16t²
for what time interval is the rocket more than 3200km above ground level

Answer 1

You have mixed up all your units. 480 km/hr does not translate to 480t unless t is in hours. Also, that -16t^2 looks like English units with g = -32 ft/s^2
But let's just go with your numbers as given, and assume that the height is given in km, after t hours, and g = -32 km/hr^2. Then just solve
480t - 16t^2 > 3200
t^2 - 30t + 200 < 0
(t-10)(t-20) < 0
10 < t < 20
so 10 hours.

Answer 2

Thank you very mach

Answer 3

I owe you one bro thanks