The vertical component of velocity of a projectile before reaching its highest point depends on the initial conditions and the gravitational acceleration acting on it. Assuming no air resistance, the vertical component of velocity at any point during the projectile's trajectory can be calculated using the principles of projectile motion.
At the highest point of the projectile's trajectory, the vertical component of velocity becomes zero. This is because at the highest point, the projectile momentarily stops moving upward before it begins to descend due to the influence of gravity.
If we consider the projectile's initial velocity as v₀ and the angle of projection (angle with respect to the horizontal) as θ, the initial vertical velocity component (v_y) can be found by multiplying the initial velocity (v₀) by the sine of the angle (θ):
v_y = v₀ * sin(θ)
As the projectile moves upward, the vertical velocity component decreases due to the effect of gravity. At the highest point, it becomes zero. After reaching the highest point, the velocity component starts increasing in the downward direction due to the influence of gravity.
It's worth noting that the horizontal component of velocity remains constant throughout the projectile's motion (assuming no external forces act horizontally), while the vertical component changes under the influence of gravity.