An army tank on a mountainside fires its gun horizontally. The shell strikes the ground at a horizontal distance of 6000 m away from the tank. As the vertical component of the shell’s striking velocity is vy=200 m/s, how soon after it is fired does the shell strike the ground? (g=10 m/s2)
2. Relevant equations
3. The attempt at a solution
then find t with (2) but why is it the component vy?