Tham khảo tài liệu 'physics_test_bank_split_4', khoa học tự nhiên, vật lý phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http 38. A girl jogs around a horizontal circle with a constant speed. She travels one fourth of a revolution a distance of 25 m along the circumference of the circle in s. The magnitude of her acceleration is A. s2 B. s2 C. s2 D. s2 E. s2 ans C 39. A stone is tied to the end of a string and is swung with constant speed around a horizontal circle with a radius of m. If it makes two complete revolutions each second the magnitude of its acceleration is A. m s2 B. m s2 C. 24m s2 D. 240 m s2 E. 2400 m s2 ans D 40. A Ferris wheel with a radius of m makes 1 revolution every 10 s. When a passenger is at the top essentially a diameter above the ground he releases a ball. How far from the point on the ground directly under the release point does the ball land A. 0 B. C. D. E. 16 m ans D 41. A boat is able to move through still water at 20m s. It makes a round trip to a town km upstream. If the river flows at 5m s the time required for this round trip is A. 120s B. 150s C. 200 s D. 300s E. 320 s ans E 46 Chapter 4 MOTION IN TWO AND THREE DIMENSIONS Simpo PDF Merge and Split Unregistered Version - http 42. A boat is traveling upstream at 14 km h with respect to a river that is flowing at 6 km h with respect to the ground . A man runs directly across the boat from one side to the other at 6km h with respect to the boat . The speed of the man with respect to the ground is A. 10 km h B. 14 km h C. km h D. 21 km h E. 26 km h ans A 43. A ferry boat is sailing at 12 km h 30 W of N with respect to a river that is flowing at km h E. As observed from the shore the ferry boat is sailing A. 30 E of N B. due N C. 30 W of N D. 45 E of N E. none of these ans B 44. A boy wishes to row across a river in the shortest possible time. He can row at 2m s in still water and the river is flowing at 1 m s. At what angle 0 should he point the .