Math Problem Statement

A 1330-kg rocket is launched with a velocity v0 = 100 m/s against a strong wind. The wind exerts a constant horizontal force Fwind = 8450 N on the rocket. At what launch angle will the rocket achieve its maximum range? HINT: This problem might be difficult to solve analytically. HINT: You can calculate the range of a number of angles and find the maximum range and the corresponding launch angle in that manner.

Solution

To find the launch angle that maximizes the range of a rocket under the influence of a strong horizontal wind, we can approach the problem numerically by calculating the range for different angles and determining which angle gives the maximum range.

Problem Breakdown:

  • Initial velocity: v0=100m/sv_0 = 100 \, \text{m/s}
  • Rocket mass: m=1330kgm = 1330 \, \text{kg}
  • Wind force: Fwind=8450NF_{\text{wind}} = 8450 \, \text{N}
  • Gravitational acceleration: g=9.81m/s2g = 9.81 \, \text{m/s}^2

The rocket experiences two forces:

  1. Gravity: Affects the vertical motion of the rocket.
  2. Wind force: Exerts a horizontal force, slowing the rocket in the horizontal direction.

Motion Equations:

  • Horizontal motion: The horizontal force is due to both the rocket’s thrust and the wind. The acceleration due to the wind is: awind=Fwindma_{\text{wind}} = \frac{F_{\text{wind}}}{m} This affects the horizontal velocity, which will be: vx=v0cos(θ)awindtv_x = v_0 \cos(\theta) - a_{\text{wind}} t

  • Vertical motion: The vertical velocity is influenced only by gravity: vy=v0sin(θ)gtv_y = v_0 \sin(\theta) - g t

Range Calculation:

We know the rocket will reach its maximum range when it returns to the ground (y=0y = 0). We can calculate the time to reach the ground by solving for tt when y(t)=0y(t) = 0.

  1. Use the vertical motion equation to find the time of flight: y(t)=v0sin(θ)t12gt2y(t) = v_0 \sin(\theta) t - \frac{1}{2} g t^2 Setting y(t)=0y(t) = 0 and solving for tt, we get the total flight time: tflight=2v0sin(θ)gt_{\text{flight}} = \frac{2 v_0 \sin(\theta)}{g}

  2. Using this flight time, we can now calculate the horizontal distance (range) by integrating the horizontal velocity over the time of flight: R(θ)=0tflight(v0cos(θ)Fwindmt)dtR(\theta) = \int_0^{t_{\text{flight}}} \left(v_0 \cos(\theta) - \frac{F_{\text{wind}}}{m} t \right) dt Solving this gives: R(θ)=v0cos(θ)tflightFwindmtflight22R(\theta) = v_0 \cos(\theta) t_{\text{flight}} - \frac{F_{\text{wind}}}{m} \frac{t_{\text{flight}}^2}{2}

Numerical Solution:

Since this equation is complex and depends on the angle θ\theta, we will calculate the range for different angles (e.g., 00^\circ to 9090^\circ) and determine which angle yields the maximum range.

Let me compute the result numerically.The launch angle that maximizes the rocket's range, given the wind force, is approximately 28.56°. At this angle, the maximum range the rocket can achieve is about 554.29 meters.

Would you like more details on the calculations or any further clarifications?

Here are five related questions:

  1. How would the result change if the wind force increased?
  2. What if the initial velocity were higher? How would the optimal angle shift?
  3. How does air resistance (not just wind) affect projectile motion?
  4. Can we calculate the energy lost due to the wind?
  5. What would happen if there were no wind? What would the optimal angle be?

Tip: In real-world physics problems, numerical methods like this are often necessary when analytic solutions are difficult or impossible.

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Math Problem Analysis

Mathematical Concepts

Projectile Motion
Kinematics
Numerical Methods

Formulas

Horizontal acceleration due to wind: a_wind = F_wind / m
Horizontal velocity: v_x = v_0 * cos(θ) - a_wind * t
Vertical velocity: v_y = v_0 * sin(θ) - g * t
Flight time: t_flight = (2 * v_0 * sin(θ)) / g
Range: R(θ) = v_0 * cos(θ) * t_flight - (F_wind / m) * (t_flight^2) / 2

Theorems

Projectile motion under external forces
Numerical range optimization

Suitable Grade Level

College-level Physics