phy
posted by ikye .
(Q1)A 40N force applied at an angle of 37c above the horizontal pulls a 5kg box on a horizontal floor. The acceleration of the box is 3m/s2,How large a frctional force must be retarding the motion of the box. (a)50 N(b)13N(c)17N(d)25N (Q2) A block of mass 2kg is connected to a freely hanging block of mass 4kg by a light and inextensible string which passes over pulley at the edge of a table. The 2kg mass is on the surface of the table assumed to be smootm.Calculate the acceleration of the system and the tension in the string (a)6.7m/s2 and13.3N(b)3.3 m/s2 and 34.4N (c)0.54m/s2 40.6N(d)2.5 m/s2 and 32.2N (Q3)A 20kg block on an inclined plane is pulled up the plane with a rope tied to the block. The rope is at angle of 37c above the surface of the plane.The tension in the rope is 250N and the frictional force on the block is 8.0N.What is the acceleration of the block?

1. Fn = m*a
40*cos37Fk = 5 * 3
31.9Fk = 15
Fk = 31.915 = 17 N.
3. a = Fn/m
a = (250*cos378)/20 = 9.58 m/s^2.