Question 3 of 15  |  Physics > Mechanics > Newton's Laws  |  Medium  |  Problem type: Incline + Friction  |  Time spent: 1:42
Q3  |  Single Correct MCQ
A block of mass 5 kg is placed on a rough inclined plane (angle of inclination = 30°, μ = 0.4). A horizontal force F is applied to the block. The block is on the verge of moving up the incline. Find the magnitude of F. (Take g = 10 m/s²)

Given: sin 30° = 0.5, cos 30° = 0.866, tan 30° = 0.577

My Approach (write your reasoning / method before solving)
Hint: Resolve the horizontal force F into components along and perpendicular to the incline. Remember: when the block is about to move up, friction acts down the incline. Normal force = mg·cosθ − F·sinθ (because F has a component pushing into the surface).