Question

Name 1. An external force (someone pulling on the end of the rope) of 125 N is applied to the rope. (a) Find the magnitude and acceleration of the box. (b) Find the magnitude of the applied force that will cause the box to move down at a constant speed. (c) Would the applied force be the same if the box were moving up at a constant speed? If yes, explain why. If no, find the applied force.

Answer 1

Fapp Fapp is the applied force, then tension in the rope. will be T= fapt If Pulleys are ideel, then net force on the bulley must be zero. IT, = 2T I = T = 2 Fabb FBD of m, 1. m L La) Using Newton's law on m, mg - 2T, = ma mg - 4 Fapp = ma a= mg - 4F apb m

ginen, m= 55 kg , En ros 125 N using g = 9,8 m/s² a = (55x9-) – (**125) m/ - 55 I am o 7 m/s2 (6) When block is moving downward with constant MA inwa Speed. ατο , * 4 Fapp = mg Fapp = mg 1 (c) when block is moving upward with Cons. Speed again a=0 which gives 4 Fapp = mg 1 Fapp = my le which is same as part 6