A runner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. Let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. The runner starts at (x,y) = (50m, 0m) and runs 2.5 times around the track in aclockwise direction. What is his displacement vector? Give your answer as a magnitude and direction.
Ch 03: Vectors and Coordinate Systems
3장, 문제 11a
Draw each of the following vectors, label an angle that specifies the vector's direction, then find its magnitude and direction. B = -4.0i + 4.0j
검증된 단계별 안내1
Step 1: Understand the vector components. The vector B is given in component form as \( B = -4.0\mathbf{i} + 4.0\mathbf{j} \), where \( \mathbf{i} \) represents the x-direction and \( \mathbf{j} \) represents the y-direction. This means the x-component of the vector is \( -4.0 \) and the y-component is \( 4.0 \).
Step 2: Draw the vector. Plot the vector on a Cartesian coordinate system. Start at the origin \( (0, 0) \), move \( -4.0 \) units along the x-axis (to the left), and then move \( 4.0 \) units along the y-axis (upward). Draw an arrow from the origin to the point \( (-4.0, 4.0) \). Label the angle \( \theta \) between the vector and the negative x-axis.
Step 3: Calculate the magnitude of the vector. Use the Pythagorean theorem: \( |B| = \sqrt{(B_x)^2 + (B_y)^2} \), where \( B_x = -4.0 \) and \( B_y = 4.0 \). Substitute these values into the formula: \( |B| = \sqrt{(-4.0)^2 + (4.0)^2} \).
Step 4: Determine the direction of the vector. The direction \( \theta \) is the angle the vector makes with the positive x-axis. Use the formula \( \theta = \arctan\left(\frac{B_y}{B_x}\right) \). Substitute \( B_x = -4.0 \) and \( B_y = 4.0 \): \( \theta = \arctan\left(\frac{4.0}{-4.0}\right) \). Note that the vector lies in the second quadrant, so adjust the angle accordingly to reflect its position.
Step 5: Express the final magnitude and direction. The magnitude is the result from Step 3, and the direction is the adjusted angle from Step 4. Ensure the direction is expressed in degrees or radians, as required, and clearly indicates the vector's orientation relative to the positive x-axis.

비슷한 문제에 대한 검증된 영상 답변:
이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m도움이 되었나요?
주요 개념
질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.
Vector Representation
Vectors are quantities that have both magnitude and direction, represented in a coordinate system. In this case, the vector B = -4.0i + 4.0j can be visualized in a 2D Cartesian plane, where 'i' represents the x-axis and 'j' represents the y-axis. The components indicate that the vector points left (negative x-direction) and up (positive y-direction).
추천 영상:
가이드 코스
Adding 3 Vectors in Unit Vector Notation
Magnitude of a Vector
The magnitude of a vector is a measure of its length and can be calculated using the Pythagorean theorem. For vector B, the magnitude is found by taking the square root of the sum of the squares of its components: |B| = √((-4.0)² + (4.0)²) = √(16 + 16) = √32, which simplifies to 4√2. This value represents how far the vector extends from the origin.
추천 영상:
가이드 코스
Calculating Magnitude & Components of a Vector
Direction of a Vector
The direction of a vector is specified by the angle it makes with a reference axis, typically the positive x-axis. This angle can be calculated using the arctangent function: θ = arctan(y/x). For vector B, the angle can be found as θ = arctan(4.0 / -4.0), which gives an angle in the second quadrant, indicating the vector's orientation in the Cartesian plane.
추천 영상:
가이드 코스
Adding 3 Vectors in Unit Vector Notation
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