Tham khảo tài liệu 'physics_test_bank_split_7', 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 24. An ideal spring with a pointer attached to its end hangs next to a scale. With a 100-N weight attached the pointer indicates 40 on the scale as shown. Using a 200-N weight instead results in 60 on the scale. Using an unknown weight X instead results in 30 on the scale. The weight of X is . 100N 40 0 A. 10N B. 20N C. 30N D. 40N E. 50 N ans E 25. Three identical ideal springs X Y Z are arranged as shown. When a mass is hung on X the mass descends cm. When a mass is hung on Y the mass descends LU u u LU Y A. cm B. cm C. cm D. cm E. cm ans E Chapter 7 KINETIC ENERGY AND WORK 91 Simpo PDF Merge and Split Unregistered Version - http 26. When a certain rubber band is stretched a distance x it exerts a restoring force of magnitude F Ax where A is a constant. The work done by a person in stretching this rubber band from x 0 to x L beginning and ending at rest is A. AL2 B. A 2L C. A 2L2 D. A L E. AL2 2 ans E 27. When a certain rubber band is stretched a distance x it exerts a restoring force of magnitude F ax bx2 where a and b are constants. The work done in stretching this rubber band from x 0 to x L is A. aL2 bLx3 B. aL 2bL2 C. a 2bL D. bL E. aL2 2 bL3 3 ans E 28. An ideal spring is hung vertically from the ceiling. When a mass hangs at rest from it the spring is extended cm from its relaxed length. A downward external force is now applied to the mass to extend the spring an additional 10cm. While the spring is being extended by the force the work done by the spring is A. B. C. X 10-5 J D. E. J ans A 29. An ideal spring is hung vertically from the ceiling. When a block hangs at rest from it the spring is extended cm from its relaxed length. A upward external force is then applied to the block to move it upward a distance of 16 cm. While the block is moving upward the work done by the spring is A. .
