Respuesta :
Answer:
V = 308.1 m/s   θ = -64º
Explanation:
a and b) Â We will use the projectile launch equations where we are asked to find the speed when the tank reaches the ground
Let's start by breaking down the speed
       Vox = Vo cos θ
       Voy = Vo sint θ
       Vox = 140 cos 15 = 135.2 m / s
       Voy = 140 sin 15 = 36.2 m / s
Let's look for vertical speed when it hits the ground
       Vy² = Voy² - 2gy
       Vy = √(36.2² - 2 9.8 3.98 103) = √ (1310-78008)
       Vy = 276.9 m / s
We have both components.
       V² = Vx² + Vy²
       V = √ (135.2² + 276.9²)
       V = 308.1 m / s
       tan θ = Vy / Vx
       tan θ = -276.9 / 135.2 = 2,048
       θ = -64º
The negative sign means that it is measured from the x-axis clockwise
c and d)  We repeat the same calculation for tank B, the only difference is the angle T = -15º
       Vox = 140 cos (-15)
       Voy = 140 sin (-15)
       Vox = 135.2 m / s
       Voy = 140 sin (-15)
       Voy = -36.2 m / s
We calculate the vertical speed
       Vy² = Voy² - 2 g Y
       Vy = √ ((-36.2)² - 2 9.8 3980)
       Vy = 276.9 m / s
       V = √(135.3²2 + 276.9²)
       V = 308.1 m/s
  Â
       tan θ = -276.9 / 135.2
       θ = -64
You can see that the speeds and angles are the same in both cases, the difference between these two situations is in the horizontal distance that runs each story