1. [-/8 Points] DETAILS The figure shows four boxes (numbered 1 to 4 from left to right) being pulled across a frictionless floor by force F of 25 newtons on Cord 4. Corda Box 1 Box 2 Cord 3 Box 4 Box 3 Fig. 5-26 (A) Rank the boxes according to their accelerations, greatest first (use only the symbols > or =, for example 1=4>3=2). (B) Rank the cords according to their tension, greatest first (use only the symbols > or =, for example 4=1>2=3). 2. [-/4 Points] DETAILS The engine of a locomotive exerts a constant force of 7.5 x 103 N to accelerate a train to 70 km/h. Determine the time taken for the train of mass 1.7 x 10' kg to reach this speed from rest.10. [-/4 Points] DETAILS A dockworker loading crates on a ship finds that a 21.kg crate, Initially at rest on a horizontal surface, requires a 74-N horizontal force to set it in motion. However, after the crate is In motion, a horizontal force of 55 N is required to keep it moving with a n crate and floor and calculate their ratio: M& HE3. [-/15 Points] DETAILS Two blocks each of mass m = 3.57 kg are fastened to the top of an elevator as in the figure below. TI m 12 (a) If the elevator has an upward acceleration a = 1.60 m/s', find the tensions 7, and 72 in the upper and lower strings. 71 T2 =[ (b) If the strings can withstand a maximum tension of 89.0 N, what maximum acceleration can the elevator have before the upper string breaks? 4. [-/12 Points] DETAILS In the figure below, m, = 11.0 kg and my = 4.5 kg. The coefficient of static friction between m, and the horizontal surface is 0.60, and the coefficient of kinetic friction is 0.30. (a) If the system is released from rest, what will its acceleration be? (Enter the magnitude of the acceleration.) (b) If the system is set in motion with my moving to the right (my moving downward), what will be the acceleration of the system? (Enter the magnitude of the acceleration.) c) If the system is set in motion with m, moving to the left (m2 moving upward), what will be the acceleration of the system? (Enter the magnitude of the acceleration.)