A swimmer can swim with Velocity of 10 km/h. w.r.t, the water flowing in a river with velocity of 5 km/h. In what direction should he swim to reach the point on the other bank just opposite to his starting point?

A man can swim with a speed of 4.0 km/h in still water. How long does he take to cross a river 1.0 km wide if the river flows steadily at 3.0 km/h and he makes his strokes normal to the river current? How far down the river does he go when he reaches the other bank?

Two towns A and B are connected by a regular bus service with a bus leaving in either direction every T minutes. A man cycling with a speed of 20 km h~1 in the direction A to B notices that a bus goes past him every 18 min in the direction of his motion, and every 6 min in the opposite direction. What is the period T of the bus service and with what speed - (assumed constant) do the buses ply on the road?

A trolley of mass 200 kg moves with a uniform speed of 36 km/ h on a frictionless track. A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with a speed of 4 m s^-1 relative to the trolley in a direction opposite to the its motion, and jumps out of the trolley. What is the final speed of the trolley? How much has the trolley moved from the time the child begins to run?

The speed of a boat is 5 km/h in still-water. It crosses a river of width 1 km along the shortest path in 20 min. The velocity of river water in km/h is

A man walks on a straight road from his home to a market 2.5 km away with a speed of 5 km h ^-1 . Finding the market closed, he instantly turns and walks back home with a speed of 7.5 km h^-1 . What is the average speed of the man over the interval of time (i) 0 to 30 min, (ii) 0 to 50 min, (Hi) 0 to 40. min? [Note: You will appreciate from this exercise why . it is better to define average speed as total path length divided by time, and not as magnitude of average velocity. You would not like to tell the tired man on his return home that his average speed was zero!]

A driver of a car travelling at 52 km h^-1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h^-1 in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelle farther after the brakes were applied?

A man walks on a straight road from his home to a market 2.5 km away with a speed of 5 km h ^-1 . Finding the market closed, he instantly turns and walks back home with a speed of 7.5 km h^-1 . What is the magnitude of average velocity.

Give the magnitude and direction of the net force acting onfa) a drop of rain falling down with a constant speed. (b) a cork of mass 10 g floating on water. (c) a kite skillfully held stationary in the sky. (cf) a car moving with a constant velocity of 30 km/h on a rough road.