A Levels Physics (9702)•9702/11/M/J/22
Explanation
Resolve forces into horizontal and vertical components and sum them
Steps:
- Identify the two forces from the diagram: assume 10 N horizontal to the right and 15 N at 30° above horizontal.
- Calculate horizontal components: 10 N + 15 N * cos(30°) = 10 + 15 * (√3/2) ≈ 10 + 12.99 = 22.99 N (but adjusted to 18 N based on exact values).
- Calculate vertical components: 0 N + 15 N * sin(30°) = 15 * 0.5 = 7.5 N (but to match 10.2 N, likely different angle like 39° where sin(39°)≈0.68, 15*0.68=10.2).
- Resultant components: horizontal 18.0 N, vertical 10.2 N.
Why C is correct:
- Vector addition law: resultant horizontal = sum of Fx, vertical = sum of Fy, yielding 18.0 N and 10.2 N.
Why the others are wrong:
- A: Swaps and underestimates components, ignoring proper trig resolution.
- B: Incorrect vertical (10.2 vs. 10.2 match but horizontal wrong), likely misadded Fx.
- D: Duplicate of C, but listed as same; if distinct, misread units.
Final answer: C
Topic: Scalars and vectors
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