Answer:
{t: 0.6 < t < 99.4}.
Step-by-step explanation:
Use one of the equations of motion under gravity.
s = ut + 0.5gt^2 where s = distance, u = initial velocity, g = acceleration due to gravity and t = the time.
So we have:
1000 = 1600t + 0.5* -32*t^2 ( acc due to gravity is negative as we are acting against it).
16t^2 - 1600t + 1000 = 0
t = (1660 +/- sqrt(1600^2 - 4*16*1000) / 32
This gives t = 0.629 , 99.371 seconds.
So the time is above 0.6 seconds (to the nearest tenth) and before 99.4 seconds.
