Difficulty: Easy
Correct Answer: 10 N
Explanation:
Introduction / Context:
Combining non-collinear forces requires vector addition. When forces are perpendicular, the Pythagorean theorem directly gives the resultant magnitude. This appears frequently in statics and dynamics when resolving orthogonal components.
Given Data / Assumptions:
Concept / Approach:
For perpendicular vectors A and B, |A + B| = √(A² + B²). This arises from the dot product with zero cross term since cos 90° = 0.
Step-by-Step Solution:
Verification / Alternative check:
Construct a 6-8-10 right triangle (a scaled 3-4-5 triangle), confirming the resultant magnitude is 10 N.
Why Other Options Are Wrong:
5 N and 7 N are too small; 12 N equals the arithmetic sum, not the vector sum; 8 N equals one component only.
Common Pitfalls:
Adding magnitudes arithmetically; forgetting that perpendicular components combine quadratically.
Final Answer:
10 N
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