Question

A projectile is shot from the ground at a velocity of `19 m/s` and at an angle of `(pi)/2`. How long will it take for the projectile to land?

Answer 1

The projectile takes `3.87s` to land.

Explanation:

In this particular case there is only the vertical component of motion (because angle is 90°). We consider the equation `s=vt-1/2at^2` and assume `s=0`. So `t(v-1/2at)=0` and `t=2v/g=(2*19m/s)/(9.81m/s^2)=3.87s.`
That's all.