Math Problem Statement

If it takes 1409 foot-pounds of work for a 50 pound force to move an object a distance of 30 feet along a horizontal sidewalk, then at what angle relative to the sidewalk is the force being applied to the object? Round your answer to the nearest degree.

Solution

To determine the angle at which the force is applied, we can use the work-energy principle, which states that the work done is equal to the force applied times the distance moved in the direction of the force.

Given:

  • Work done (W) = 1409 foot-pounds
  • Force (F) = 50 pounds
  • Distance (d) = 30 feet

The work done can be expressed as: W=Fdcos(θ)W = F \cdot d \cdot \cos(\theta) where θ\theta is the angle between the force and the direction of motion.

We can rearrange the formula to solve for cos(θ)\cos(\theta): cos(θ)=WFd\cos(\theta) = \frac{W}{F \cdot d}

Now, substituting the values: cos(θ)=14095030\cos(\theta) = \frac{1409}{50 \cdot 30} cos(θ)=140915000.9393\cos(\theta) = \frac{1409}{1500} \approx 0.9393

Next, we find θ\theta by taking the arccosine: θ=cos1(0.9393)20.9\theta = \cos^{-1}(0.9393) \approx 20.9^\circ

Rounding to the nearest degree gives: θ21\theta \approx 21^\circ

Thus, the angle at which the force is being applied is approximately 21 degrees relative to the sidewalk.

Questions for Further Exploration:

  1. How does the angle of the applied force affect the efficiency of work done?
  2. What would happen if the force was applied vertically instead of at an angle?
  3. How would the work change if the distance was increased to 50 feet?
  4. What other factors can affect the total work done on the object?
  5. How can we calculate the vertical and horizontal components of the force?

Tip:

To analyze forces at angles, remember to always resolve them into their horizontal and vertical components for clearer calculations.

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Math Problem Analysis

Mathematical Concepts

Work-Energy Principle
Trigonometry
Cosine Function

Formulas

W = F * d * cos(θ)
cos(θ) = W / (F * d)

Theorems

Work-Energy Theorem

Suitable Grade Level

Grades 10-12