A projectile is fired with an initial speed of 34.7 m at an angle of 67.3o above the horizontal on a long flat firing range. Determine total time in the air.

Answer 1

vertical problem
Vi = 34.7 sin 67.3
h = 0 + Vi t - 4.9 t^2
when is the height h = 0 ?
0 = Vi t - 4.9 t^2 = t ( Vi - 4.9 t)
so it is on the ground when t = 0 (as we knew) and at t = Vi/4.9)