Answer: 11.25 m/s opposite.
- A 3 m/s opposite
- B 5 m/s opposite
- C 7.5 m/s opposite
- D 11.25 m/s opposite
Correct answer: D. 11.25 m/s opposite
Explanation: Conservation of momentum: 0 = 60 x 7.5 + 40 x v<sub>boat</sub>. v<sub>boat</sub> = -450/40 = -11.25 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.