_ 3 _ A proton moves in a horizontal line accordingto the function S (t) _ 4t 6t + 3, t 2 0 1 wheret is measured in seconds, and 3 is measured in inches. Answer the following questions labeling your answers with proper units, if appropriate. a. Find the velocity of the proton at time t. b. Find the acceleration of the proton at time t. c. At what time t is the proton moving at a rate of 6 inch/s? d.At what time t is the proton at rest? You may give your answer either in exact form or rounded to 4 decimal places