13. A system of two blocks is accelerated by an applied force of magnitude F on the frictionless horizontal surface. The tension in the string between the blocks is:
(A) 3F
(B) 5F
(C) 3/8 F
(D) 1/3 F
(E) 1/5 F
50 kg
14. A box of 50 kg is pulled up from rest by a cable. The tension force in the cable is 600 N. What is the box's velocity after it covers vertical distance of 16 m?
a. 4 m/s (B) 8 m/s (C) 12 m/s (D) 16 m/s (E) 20 m/s