Answer: 60m/s
Explanation:
From the diagram:
Θ = 30°
Vertical resolution (y-axis) :
Voy = VoSinΘ
g in the upward direction = negative (-) = - g
Vfinal = 0
Distance (H) traveled along y =
Time taken to reach maximum height :
From v = u + at
0 = usinΘ - gt
gt = usinΘ
t = usinΘ / g
Horizontal resolution:
S = ut + 1/2at^2
Substituting t = usinΘ / g ; Voy = usinΘ
S = (usinΘ × usinΘ / g) - 1/2 g × (usinΘ /g)^2
S = (u^2sin^2Θ / g) - (u^2sin^2Θ / 2g)
S = (u^2sin^2Θ) / 2g
Now if S = maximum height = 45m
Then,
45 = [Vo^2sin^2(30°)] / 2(10)
45 =[ Vo^2 * (0.5)^2] / 20
45 =( Vo^2 * 0.25) / 20
20 * 45 = Vo^2 * 0.25
900 / 0.25 = Vo^2
3600 = Vo^2
Vo = sqrt(3600)
Vo = 60m/s
