Polar Coordinates (r-0) 5. The slider P can be moved inward by means of the string S, while the slotted arm rotates about point O. The angular position of the arm is given t² by =0.81- where is in radians and t is in 20 9 seconds. The slider is at r = 1.6 m when t = 0 and thereafter is drawn inward at the constant rate of 0.2 m/s. Determine the magnitude and direction (expressed by the angle relative to the positive x- axis) of the velocity and acceleration of the slider when t = 4 s. Ans. 0.377 m/s, 259.5°; 0.272 m/s², 19.4° y S Ꮎ