Answer: 4.8 m/s.
- A 4.8 m/s
- B 9.6 m/s
- C 12 m/s
- D 24 m/s
Correct answer: A. 4.8 m/s
Explanation: a = F/m = 3t/5 = 0.6t. v = integral of 0.6t dt = 0.3t<sup>2.</sup> At t=4: v = 0.3 x 16 = 4.8 m/s.
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.