PAGE DATE Assignment # 6 : Solve Completely 1 . A body falls from rest of the resistance of the air is proportional to the speed, and if the limiting speed is 160 ft / sec , find the speed at the end of 5 sec -2. A certain radioactive substance has a half-life of 38 hours . Find how long it takes for 90 % of the radioactivity to be dissipated 3 . Solve for the General Solution of xy " + y' = 4x 4. A particle moves so that its position at time t ( seconds ) is given by the equation x = 4cos 3t, 4= 4 sin t , where x and y are expressed in feet . show that the particle traverses a circle , and find at and / anl for the particle. ( note: at = dv/ dt and ! an! = y? / R - radius of curvature) 5 . A particle moves clockwise around the circle * 2+ y? = 16 with VX = aft / sec. When x = 2 , find a and p (a = ( ax? + ay? ) " ; Q = tan" Q = aylax) 6 . Solve completely : y" - y' - 24 = 4x 7. Choose an application problem , and solve it with complete solution