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A plane is being tracked by radar, and data is taken every second in polar coordinates

θ and r

t (sec) 200 202 204 206 208 210

θ (rad) 0. 75 0. 72 0. 70 0. 68 0. 67 0. 66

r (m) 5120 5370 5560 5800 6030 6240

1. Calculate the velocity of the plane as a function of time, where the velocity V is given by:

V= √r^2 + r(θ)^2.

Please compute the derivatives using the most accurate finite-difference method and comment on the choices you made (why did you choose to use a certain method at any given point).

1 Answer

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Step-by-step explanation:

To calculate the velocity of the plane as a function of time, we need to compute the derivatives of the given polar coordinates, θ and r, with respect to time (t). We can use finite-difference methods to approximate these derivatives accurately.

There are several finite-difference methods available, such as forward difference, backward difference, and central difference. Each method has its advantages and limitations. In this case, we'll use the central difference method, which provides a more accurate approximation by considering neighboring data points on both sides.

Given data points:

t = [200, 202, 204, 206, 208, 210]

θ = [0.75, 0.72, 0.70, 0.68, 0.67, 0.66]

r = [5120, 5370, 5560, 5800, 6030, 6240]

To calculate the velocity V = √r^2 + r(θ)^2, we need to compute the derivatives dθ/dt and dr/dt.

1. Calculate dθ/dt (approximation):

To approximate dθ/dt, we'll use the central difference method. Since the time interval between consecutive points is 2 seconds, we can use the formula:

dθ/dt ≈ (θ[i+1] - θ[i-1]) / (t[i+1] - t[i-1])

For i = 1 to 4 (excluding the first and last data points), the central difference formula can be applied. For the first and last points, we'll use forward and backward difference respectively.

dθ/dt = [(θ[2] - θ[0]) / (t[2] - t[0]),

(θ[3] - θ[1]) / (t[3] - t[1]),

(θ[4] - θ[2]) / (t[4] - t[2])]

2. Calculate dr/dt (approximation):

Similar to dθ/dt, we'll use the central difference method to approximate dr/dt.

dr/dt ≈ (r[i+1] - r[i-1]) / (t[i+1] - t[i-1])

For i = 1 to 4 (excluding the first and last data points), the central difference formula can be applied. For the first and last points, we'll use forward and backward difference respectively.

dr/dt = [(r[2] - r[0]) / (t[2] - t[0]),

(r[3] - r[1]) / (t[3] - t[1]),

(r[4] - r[2]) / (t[4] - t[2])]

3. Calculate V (velocity):

Using the derived values of dθ/dt and dr/dt, we can calculate V = √(r^2 + r(θ)^2) using the given formula.

V = √(r^2 + r(θ)^2)

Please note that we are assuming uniform time intervals between the data points. Additionally, as with any finite-difference method, the accuracy of the approximation increases with smaller time intervals.

User Marchelle
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