A particle of mass m is suspended from the ceiling of a hollow block a massless cord as shown in the figure . the block is pulled up a wedge that makesan angle ɸ  with the horizontal at a constant accelaration a . ıf the cord makes aconstant angle Ɵ the perpendicular to the ceiling , what is a in terms of ɸ , Ɵ and gravitational acceleration g. ( g= 10m/s2 )

(a) An elevator of mass m moving upward has two forces acting on it: the upward force of tension in the cable and the downward force due to gravity. When the elevator is accelerating upward, which is greater, T orw? (b) When the elevator is moving at a constant velocity upward, which is greater, T or w? (c) When the elevator is moving upward, but the acceleration is downward, which is greater, T or w? (d) Let the elevatorhave a mass of 1 500 kg and an upward acceleration of 2.5 m/s2. Find T. Is your answer consistent with the answer to part (a)? (e) The elevator of part (d) now moves with a constant upward velocity of 10 m/s. Find T. Is your answer consistent with your answer to part (b)? (f) Having initially moved upward with a constant velocity, the elevator begins to accelerate downward at 1.50 m/s2. Find T. Is your answer consistent with youranswer to part (c)?

As shown in Fig. 4–70, five balls (masses 2.00, 2.05, 2.10, 2.15, 2.20 kg) hang from a crossbar. Each mass is sup- ported by "5-lb test" fishing line which will break when its tension force exceeds 22.2 N (= 5.00 lb). When this device is placed in an elevator, which accelerates upward, only the lines attached to the 2.05 and 2.00 kg masses do not break. Within what range is the elevator's acceleration? 2.20 2.15 2.10 .05 2.00 kg| FIGURE 4-70 Problem 84.