Table of contents
- 0. Review of College Algebra4h 43m
- 1. Measuring Angles39m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
8. Vectors
Geometric Vectors
Problem 7.39
Textbook Question
To build the pyramids in Egypt, it is believed that giant causeways were constructed to transport the building materials to the site. One such causeway is said to have been 3000 ft long, with a slope of about 2.3°. How much force would be required to hold a 60-ton monolith on this causeway?
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<Step 1: Convert the weight of the monolith from tons to pounds. Since 1 ton is equal to 2000 pounds, multiply 60 tons by 2000 to get the weight in pounds.>
<Step 2: Identify the force component parallel to the slope. This is the force that needs to be counteracted to hold the monolith in place. Use the formula for the parallel component of gravitational force: \( F_{\text{parallel}} = W \cdot \sin(\theta) \), where \( W \) is the weight of the monolith and \( \theta \) is the angle of the slope.>
<Step 3: Substitute the known values into the formula. Use the weight in pounds from Step 1 and the angle of 2.3° to find \( F_{\text{parallel}} \).>
<Step 4: Calculate \( \sin(2.3°) \) using a calculator or trigonometric table to find the sine of the angle.>
<Step 5: Multiply the weight of the monolith by \( \sin(2.3°) \) to find the force required to hold the monolith on the slope.>
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Trigonometric Functions
Trigonometric functions, such as sine, cosine, and tangent, relate the angles of a triangle to the lengths of its sides. In this context, the slope of the causeway can be analyzed using these functions to determine the vertical height and the angle of inclination, which are essential for calculating the force required to hold the monolith.
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Forces and Weight
Understanding forces, particularly weight, is crucial in this scenario. The weight of the monolith, given as 60 tons, can be converted into a force using the equation F = mg, where m is mass and g is the acceleration due to gravity. This force acts downwards and must be countered by the force exerted along the slope of the causeway.
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Inclined Plane Mechanics
An inclined plane is a flat surface tilted at an angle, which affects how forces are distributed. The force required to hold an object on an incline can be calculated using the formula F = W * sin(θ), where W is the weight of the object and θ is the angle of the incline. This concept is vital for determining how much force is needed to keep the monolith stationary on the slope.
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Example 2
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