Aparticle moves along the x axis. its position is given by the equation with x in meters and t in seconds. determine
(a) its position at the instant it changes direction and
(b) its velocity when it returns to the position it had at t = 0.

While goofing off at the ice skating rink, a student takes off her shoes and places each of them on the ice. her friend, a hockey player, then shoots a hockey puck at each shoe. the first puck immediately comes to rest after it collides with the left shoe. the second puck rebounds after it collides with the right shoe. if each hockey puck has the same incoming speed, which shoe has greater speed after the collision? the right shoe. both shoes have the same speed. the left shoe.