Laws of Motion and Friction: JEE — Tilting Board MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

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JEE — Tilting BoardHardQuestion 30271

Question

A block (mass m) on an incline tilted at angle θ has normal force N and friction f. If the incline is tilted further until θ = 90°, the friction is:

A
mg
Correct
B
0
C
Undefined
D
mg cosθ

Correct answer

Explanation

At θ = 90°, the incline is vertical. Normal force = 0 (surface is parallel to gravity). If the block is held: friction = mg (preventing downward fall). If μ is insufficient, the block slides.

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