Answer: 4800 N.
- A 1200 N
- B 2400 N
- C 4800 N
- D 9600 N
Correct answer: C. 4800 N
Explanation: v<sup>2</sup> = u<sup>2</sup> + 2as: 0 = 400 + 2a x 50, a = -4 m/s<sup>2.</sup> F = ma = 1200 x 4 = 4800 N.
Free-body diagram of a block on an incline: weight (mg) resolves into mg sinθ along the slope and mg cosθ into the slope, balanced by the normal force N and friction f.
Concept context
Newton's three laws, friction, circular motion, and free body diagrams.