In the figure, two blocks of masses m and 3m are linked by a light, inextensible rope that passes through an ideal pulley. Block m is tied to a spring with force constant k that joins it to the floor. Initially, the spring is in its equilibrium position and the entire system is at rest. a) Find the maximum distance x that the spring elongates if the system starts from rest.
b) What is the speed of the blocks when they have travelled half that distance?

16. a brave but inadequate rugby player is being pushed backward by an opposing player who is exerting a force of 800 n on him. the mass of the losing player plus equipment is 90.0 kg, and he is accelerating at 1.20m/s2 size 12{1 "." "20"" m/s" rsup { size 8{2} } } {} backward. (a) what is the force of friction between the losing player’s feet and the grass? (b) what force does the winning player exert on the ground to move forward if his mass plus equipment is 110 kg? (c) draw a sketch of the situation showing the system of interest used to solve each part. for this situation, draw a free-body diagram and write the net force equation.