Answer:
v = √(v²₀Sin² Ф -2ghₐ)
Explanation:
According to the Law of vertical motion under gravity:
V² = U² ± 2gH--------------------------------------------------------------- (1)
V = final velocity
U = Initial velocity
g = acceleration due to gravity
H = Height of object
According to the question,
V = v
U = v₀
H = hₐ
Substituting into (1)
v² = v₀² - 2ghₐ ---------------------------------------------------------------------- (2)
The minus sign was used in the question because the object motion is against gravity.
Since the object was projected at an angle Ф to the horizontal, the vertical component of the initial velocity is given as :
v₀Sin Ф
Substituting into equation (2) we have:
v² = v²₀Sin² Ф -2ghₐ
v = √(v²₀Sin² Ф -2ghₐ)---------------------------------------------------------------- (3)