A particle which moves with curvilinear motion has coordinates in millimeters which vary with the time t in seconds according to x = 6.2+ - 3.7t and y = 2.4t2- t3/3.1. Determine the magnitudes of the velocity v and acceleration a and the angles which these vectors make with the x-axis when t = 2.8 s. Answers: When t = 2.8 s, v = i 33.89 mm/s, 0x = i 18.82 a= i 12.84 mm/s, ex- i 14.46