Math Problem Statement

A baseball, hit 4.5 feet above the ground, leaves the bat at an angle of 53 degrees and is caught by an outfielder 4 feet above the ground and 203 feet from home plate. Neglecting air resistance, what was the initial speed of the ball?

Solution

To find the initial speed of the baseball, we can apply the physics of projectile motion. Here are the known variables and assumptions based on the problem:

  • Initial height: y0=4.5y_0 = 4.5 feet.
  • Final height: yf=4y_f = 4 feet.
  • Horizontal distance: x=203x = 203 feet.
  • Angle of projection: θ=53\theta = 53^\circ.
  • Acceleration due to gravity: g=32.2ft/s2g = 32.2 \, \text{ft/s}^2 (since the problem is in feet).

The equations for projectile motion are:

  1. Horizontal motion (no acceleration in the horizontal direction): x=v0cos(θ)tx = v_0 \cos(\theta) \cdot t where v0v_0 is the initial speed, and tt is the time of flight.

  2. Vertical motion (affected by gravity): yf=y0+v0sin(θ)t12gt2y_f = y_0 + v_0 \sin(\theta) \cdot t - \frac{1}{2} g t^2

Step 1: Solve for time of flight using horizontal motion

Rearrange the horizontal motion equation to solve for time tt: t=xv0cos(θ)t = \frac{x}{v_0 \cos(\theta)} Substitute this expression for tt into the vertical motion equation.

Step 2: Solve for v0v_0

Substitute the time expression into the vertical motion equation: yf=y0+v0sin(θ)xv0cos(θ)12g(xv0cos(θ))2y_f = y_0 + v_0 \sin(\theta) \cdot \frac{x}{v_0 \cos(\theta)} - \frac{1}{2} g \left( \frac{x}{v_0 \cos(\theta)} \right)^2 Simplifying, we get: yf=y0+xtan(θ)gx22v02cos2(θ)y_f = y_0 + x \tan(\theta) - \frac{g x^2}{2 v_0^2 \cos^2(\theta)} Now, solve this equation for v0v_0.

Let me calculate this next.The initial speed of the baseball was approximately 82.39ft/s82.39 \, \text{ft/s}.

Would you like further details or have any questions?

Here are 5 follow-up questions:

  1. How would the initial speed change if the launch angle was increased?
  2. What would happen to the flight time if air resistance was considered?
  3. How does the height difference between launch and landing points affect the initial speed calculation?
  4. What would the horizontal range be if the initial height and landing height were the same?
  5. How would the calculation differ if the game were played at a higher altitude, where gravity is slightly weaker?

Tip: Always convert angles to radians when using trigonometric functions in physics calculations!

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Math Problem Analysis

Mathematical Concepts

Projectile Motion
Trigonometry
Kinematics

Formulas

x = v_0 * cos(θ) * t
y_f = y_0 + v_0 * sin(θ) * t - (1/2) * g * t^2
y_f = y_0 + x * tan(θ) - (g * x^2) / (2 * v_0^2 * cos^2(θ))

Theorems

Projectile Motion Theorem
Trigonometric Functions
Kinematic Equations

Suitable Grade Level

Undergraduate Physics or Advanced High School