h=20t-10t^2

h=10t(2-t)

t=0 t=2

it goes up for 2 seconds(40m)

140-80= 60 divided by 20 is 3..

If you start at 100 meters then throw the ball upwards, it has to go up a while, then back down. The ball will have to travel at some type of angle so it doesn’t hit the building again… but what angle will you throw it at? You have to know the angle the ball was thrown. In addition, I think you also have to know how heavy the ball is… a tennis ball travels a lot higher than a bowling ball when they are both thrown upwards at 20 meters per second.

then take that height factor gravity as acceleration till the ball drops to 80 so 100+height ball was when started to fall +20=total distance

20m per second

5 seconds to reach 100m

therefore 4 seconds x 20m equals 80m.