If you throw a ball straight up into the air at a velocity of 15 m/s you want to know how high above your hand the ball will be at exactly 2.5 sec after you released it

 Assuming that gravity has not caused the ball to start falling then after 2.5 seconds the ball will be 37.5 meters in the air

Explanation:

The ball travels 15 meters every second so for 2 seconds we would multiply 15*2=30. We have 2.5 seconds so to calculate the time traveled in half a second we would divide 15/2=7.5

Then we add 30+7.5= 37.5 meters

its c its is a mixture of gases