To solve the problem, it is necessary to apply the concepts related to the kinematic equations of the description of angular movement.
The angular velocity can be described as
Where,
Final Angular Velocity
Initial Angular velocity
Angular acceleration
t = time
The relation between the tangential acceleration is given as,
where,
r = radius.
PART A ) Using our values and replacing at the previous equation we have that
Replacing the previous equation with our values we have,
The tangential velocity then would be,
Part B) To find the displacement as a function of angular velocity and angular acceleration regardless of time, we would use the equation
Replacing with our values and re-arrange to find
That is equal in revolution to
The linear displacement of the system is,
Answer:
a) 52.915 m
b) The vertical velocity is approximately 21.092 m/s
The resultant velocity is approximately 26.5 m/s
Explanation:
a) The height of the window in the house from which the water was thrown = 15 m
The speed of the stream of water thrown = 20 m/s
The angle at which the water was thrown = 37° over the horizontal
The acceleration due to gravity, g = 10 m/s²
a) The distance from the base of the house at which the water will fall is given as follows;
y = y₀ + u·t·sin(θ) + 1/2·g·t²
Where;
y = The vertical height reached
u = The initial velocity
t = Time of flight
From the point the steam of water is thrown, we get;
y₀ = 15 m
Therefore;
y = 15 + 20 × t × sin(37°) - 1/2 × 10 × t²
y = 15 + 20 × t × sin(37°) - 5 × t²
When y = 0, Ground level, we get
0 = 15 + 20 × t × sin(37°) - 5 × t²
5·t² - 20×sin(37°)×t -15 = 0
∴ t = (20 ×sin(37°) ± √((-20 × ·sin(37°))² - 4 × (5) × (-15)))/(2 × 5)
t ≈ 3.3128302, or t ≈ 0.906
Therefore, the time of flight of the water, t ≈ 3.3128302 seconds
The distance from the base of the house at which the water will fall = The horizontal distance travelled by the water, x
x = u·cos(θ)×t
∴ x = 20 × cos(37°) × 3.3128302 ≈ 52.915
The distance from the base of the house at which the water will fall = x ≈ 52.915 m
b) The velocity at which the water will reach the ground, 'v', is given as follows;
The vertical velocity, = u·sin(θ)·t - g·t
At the ground, t ≈ 3.3128302 seconds
∴ = 20 × sin(37) - 10 × 3.3128302 ≈ -21.092
The vertical velocity at which the water will reach the ground, ≈ 21.092 m/s (downwards)
The resultant velocity, v = √(² + vₓ²)
∴ v = √(21.092² + (0 × cos(37°))²) ≈ 26.5
The resultant velocity at which the water will reach the ground, v ≈ 26.5 m/s.