## Questions 18-19
A block of mass 3 kg , initially at rest, is pulled along a frictionless, horizontal surface with a force shown as a function of time t by the graph above.
19. The speed of the block at t=2s is
(A) 4/3m/s
(B) 8/3m/s
(C) 4m/s
(D) 8m/s
(E) 24m/s