Difficulty: Easy
Correct Answer: P - Q
Explanation:
Introduction / Context:Resultant of collinear forces is found by algebraic addition with appropriate signs. Here, the forces are opposite in sense along the same line.
Given Data / Assumptions:
Concept / Approach:Assign a positive direction; take the algebraic sum. If P is chosen positive and Q acts in the negative sense, the resultant R = P − Q. The direction will be that of the larger force, i.e., along P.
Step-by-Step Solution:
Choose +x along P. Then P = +P, Q = −Q.Algebraic sum: R = P + (−Q) = P − Q.Since P > Q, R > 0, so resultant acts along P.Verification / Alternative check:Vector diagram: two arrows in opposite directions; the smaller cancels part of the larger, leaving difference in the larger’s sense.
Why Other Options Are Wrong:
Common Pitfalls:Confusing magnitude with signed result; here only the magnitude is requested, which is the absolute difference.
Final Answer:P - Q
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