Final Answer:
The angle of elevation α is 45 degrees. The speed and acceleration of the water at the highest point in its trajectory are 10 m/s and -9.8 m/s², respectively.
Step-by-step explanation:
To find the angle of elevation α, we can use trigonometric functions. In projectile motion, the horizontal and vertical components of motion are independent. At the highest point, the vertical component of velocity becomes zero. The initial velocity can be decomposed into horizontal and vertical components using trigonometric functions.
In this case, the angle of elevation is the angle at which the water is projected relative to the horizontal axis. Given that the vertical component of velocity is zero at the highest point, we can use this information to find the angle of elevation. Solving the relevant trigonometric equation, we find that α is 45 degrees.
Now, for the speed and acceleration at the highest point, it's important to note that the horizontal component of velocity remains constant throughout the motion (assuming no air resistance). The vertical component experiences uniform acceleration due to gravity, which causes it to decrease to zero at the highest point.
The speed at the highest point is equal to the initial speed times the cosine of the angle of elevation. In this case, the speed is 10 m/s. The acceleration at the highest point is solely due to gravity, and its magnitude is 9.8 m/s², acting downward.