26.The particles describe the same circle of radius a in the same sense with the same speed v. What is their relative angular velocity?

27.A river is flowing from west to east at a speed 15 m/s. A boy on the south bank of the river, capable of swimming at 30 m/s in still water, wants to swim, cross the river in the shortest time. He should swim in direction?

28.Which of the following in not an example of linear motion?

29.Two intersecting straight lines move parallel to themselves with speed 3 m/s and 4 m/s respectively. The speed of the point of intersection of the lines, if the angle between them is 90 degree will be: