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Questions and Answers
What is the formula to find the angle between two vectors using the dot product?
What is the formula to find the angle between two vectors using the dot product?
- $ ext{cos } Θ = rac{|a| + |b|}{a ullet b}$
- $ ext{tan } Θ = rac{|a|}{|b|}$
- $ ext{sin } Θ = rac{a imes b}{|a| |b|}$
- $ ext{cos } Θ = rac{a ullet b}{|a| |b|}$ (correct)
The cross product of two vectors is always parallel to both vectors.
The cross product of two vectors is always parallel to both vectors.
False (B)
In the formula for work, which trigonometric function is used to relate the angle and the applied force?
In the formula for work, which trigonometric function is used to relate the angle and the applied force?
cosine
The magnitude of force applied times the distance moved in the direction of the force is known as ____.
The magnitude of force applied times the distance moved in the direction of the force is known as ____.
Match the following examples to their corresponding calculations:
Match the following examples to their corresponding calculations:
If two vectors have a cross product of (0,0,0), what can be inferred about those vectors?
If two vectors have a cross product of (0,0,0), what can be inferred about those vectors?
The dot product can be calculated in any dimensional space.
The dot product can be calculated in any dimensional space.
The unit of work is measured in ____ in the International System of Units.
The unit of work is measured in ____ in the International System of Units.
Flashcards
Dot Product
Dot Product
The dot product is the sum of the products of corresponding components of two vectors. It is a scalar quantity representing the projection of one vector onto another.
Angle Between Vectors
Angle Between Vectors
The angle between two vectors can be found using the dot product and the magnitudes of the vectors. The formula is: cos Θ = (a · b) / (|a| |b|).
Work (Physics)
Work (Physics)
Work is the result of force acting over a distance. It is the magnitude of the force multiplied by the distance travelled in the direction of the force. It is measured in joules.
Cross Product
Cross Product
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Cross Product of Parallel Vectors
Cross Product of Parallel Vectors
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Perpendicularity of Cross Product
Perpendicularity of Cross Product
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Study Notes
Dot Product and Cross Product of Vectors
- Dot Product (Inner Product): A way to multiply two vectors. It's calculated by multiplying corresponding components and then adding the products.
- Example: If a = (a1, a2) and b = (b1, b2), then a â‹… b = a1b1 + a2b2.
- Orthogonal Vectors: Two vectors are orthogonal if their dot product equals zero.
- Example: a = (2, -5) and b = (4, 1) . a â‹… b = (2)(4) + (-5)(1) = 8 - 5 = 3. Vectors a and b are not orthogonal.
Finding the Angle Between Vectors
- Cosine of the Angle: The dot product can be used to find the cosine of the angle between two vectors.
- Formula: cos θ = (a ⋅ b) / (|a| * |b|), where θ is the angle between the vectors a and b.
- Example: a = (6, 2), b = (-4, 3).
- |a| = √(62 + 22) = √40
- |b| = √((-4)2 + 32) = √25 = 5
- a â‹… b = (6)(-4) + (2)(3) = -24 + 6 = -18
- cos θ = -18 / (√40 * 5) ≈ -0.707
Work
- Work: The magnitude of a force applied to an object multiplied by the distance the object moves in the direction of the force.
- Formula: W = |F| * cos θ * d, where W is work, |F| is the magnitude of the force, θ is the angle between the force vector and the displacement vector, and d is the displacement.
- Example: A person pushes a car with a constant force of 120 Newtons at an angle of 45 degrees. The car moves 10 feet.
- W = 120 * cos 45° * 10 ≈ 848.5 joules
Cross Product
- Cross Product: A vector operation that's employed in 3D space; It results in a vector that is perpendicular to both the original vectors.
- Example: The cross product of vectors a and b is a new vector c and denoted by a x b = c.
- Formula: If a = (a1, a2, a3) and b = (b1, b2, b3) c = ((a2 * b3) - (a3 * b2), (a3 * b1) - (a1 * b3), (a1 * b2) - (a2 * b1))
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