posted by Abby .
A soccer ball is kicked with a speed of 9.80 m/s at an angle of 25.0 degrees above the horizontal. If the ball lands at the same level from which it was kicked, how long was it in the air?
figure the vertical velocity, then knowing the final and initial heights, solve for time in air.
Twice the time that it takes the vertical velocity component (9.80 sin 25, m/s) to become zero. The same time is required to go up as come back down. Hence the factor of two.