Math Problem Statement

A projectile is launched from a point on level ground with initial speed 19.45 miles/hour and initial angle of 37.5 degrees above the horizontal. Calculate the range of the projectile in meters. Note: Don't forget to convert units as needed.

Solution

To calculate the range of a projectile, we need to use the standard kinematic equation for the horizontal range:

R=v02sin(2θ)gR = \frac{v_0^2 \sin(2\theta)}{g}

Where:

  • v0v_0 is the initial velocity of the projectile.
  • θ\theta is the angle of projection above the horizontal.
  • gg is the acceleration due to gravity, which is approximately 9.81m/s29.81 \, \text{m/s}^2.

Step 1: Convert Initial Velocity to Meters per Second

The initial velocity v0v_0 is given in miles per hour (mph). To convert it to meters per second (m/s):

1mile=1609.34meters1 \, \text{mile} = 1609.34 \, \text{meters} 1hour=3600seconds1 \, \text{hour} = 3600 \, \text{seconds}

So, the conversion factor is: 1609.3436000.44704m/s per mph\frac{1609.34}{3600} \approx 0.44704 \, \text{m/s per mph}

Now, convert the given initial velocity: v0=19.45mph×0.44704m/s per mph8.693m/sv_0 = 19.45 \, \text{mph} \times 0.44704 \, \text{m/s per mph} \approx 8.693 \, \text{m/s}

Step 2: Plug Values into the Range Formula

Now, use the formula for range, where:

  • v0=8.693m/sv_0 = 8.693 \, \text{m/s}
  • θ=37.5\theta = 37.5^\circ
  • g=9.81m/s2g = 9.81 \, \text{m/s}^2

First, calculate sin(2θ)\sin(2\theta): 2θ=2×37.5=752\theta = 2 \times 37.5^\circ = 75^\circ sin(75)0.9659\sin(75^\circ) \approx 0.9659

Now, substitute everything into the range formula:

R=(8.693m/s)2×0.96599.81m/s2R = \frac{(8.693 \, \text{m/s})^2 \times 0.9659}{9.81 \, \text{m/s}^2}

Simplify:

R=75.5489×0.96599.8172.969.817.44metersR = \frac{75.5489 \times 0.9659}{9.81} \approx \frac{72.96}{9.81} \approx 7.44 \, \text{meters}

Final Answer:

The range of the projectile is approximately 7.44 meters.

Would you like more details or have any questions?


Here are 5 questions that extend this concept:

  1. How would the range change if the angle was increased to 45 degrees?
  2. What would happen to the range if the projectile was launched from a height instead of level ground?
  3. How would air resistance affect the range of the projectile?
  4. How can we determine the maximum height of the projectile in this scenario?
  5. What is the total time the projectile spends in the air?

Tip: Always ensure unit consistency when solving physics problems, especially when converting between imperial and metric systems.

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Math Problem Analysis

Mathematical Concepts

Projectile Motion
Kinematics
Trigonometry
Unit Conversion

Formulas

Range formula: R = (v_0^2 * sin(2θ)) / g
Velocity conversion: 1 mile = 1609.34 meters, 1 hour = 3600 seconds

Theorems

Trigonometric Identity: sin(2θ)
Kinematic Equations

Suitable Grade Level

Grades 10-12