11) Define resultant velocity. Two velocities 10 and 15 ms -1 are inclined at an angle of 60° to each other, obtain the resultant velocity: (i) by graphical method (ii) by analytical method. 12) A man can row a boat at 4 kmhr-1 in still water. He rows the boat 2 km upstream and 2 km back to his starting place in 2 hours. How fast is the stream flowing? 13) State the parallelogram law of velocities. A plane is headed north with a velocity of 400 kmhr-1 and a west wind is blowing at 70 kmhr-1. Find the distance of the plane from its base in 2 hours.