To take the boat away from the bank of a river, the boatman pushes the bank with an oar. Why?

A boat is pushed away from the river bank when a sailor jumps from the boat to the bank. Why?

The river 500 m wide is flowing with a current of 4kph. A boat starts from one bank of the river wishes to cross the river at right angle to stream direction. Boatman can row the boat at 8 kph. In which direction he should row the boat. What time he ''ll take to cross the river ?

The river 500 m wide is flowing with a current of 4kph. A boat starts from one bank of the river wishes to cross the river at right angle to stream direction. Boatman can row the boat at 8 kph. In which direction he should row the boat. What time he ''ll take to cross the river ?

A man standing on the bank of a river observes that the angle of elevation of the top of a tree just on the opposite bank is 60^(@) . The angle of elevation is 30^(@) from a point at a distance y m from the bank of the river. What is the height of the tree ?

To move a boat ahead in water, the boatman has to push the water backwards by his oar. Explain.

When a sailor jumps from a boat to the river bank?

The width of a rivers is 25m and in it water is flowing with a velocity of 4m//min . A boatman is standing on the bank of the river . He want to sail the boat to a point at the other bank which is directly opposite to him . In what time will he cross the river , if he can sail the boat at 8m//min . relative to the water ?

A boat man could row his boat with a speed 10 m/sec. He wants to take his boat from P to a point Q just opposite on the other bank of the river flowing at a speed 4 m/sec. He should row his boat–