Question

At a certain point along the path in projectile motion, the projectile has a velocity v with arrow whose scalar components are vx = +30 m/s and vy = +40 m/s. as the projectile moves along the path, what would be its minimum speed?

Answer 1

At a certain point, the velocity components are
vx = 30 m/s, the horizontal component.
vy = 40 m/s, the vertical component.

If we neglect wind resistance, then vx =  constant at 30 m/s.
However, vy = 0 at maximum height of the projectile.

The absolute velocity is
v = √(vx² + vy²).
Therefore the minimum velocity occurs when vy=0, and it is
v = vx = 30 m/s

Answer: 30 m/s