Why leaves fall from the tree when they turn yellow ?

Why do leaves have stomata?

When an apple falls from a tree what happens to its gravitational potential energy just as it reaches the ground ? After it strikes the ground ?

A person stading on the bank of a river observerves that the angle of elevation of the top of the tree on the opposite bank of the river is 60^(@) and when he retires 40 meters away from the tree the angle of elevation becomes 30^(@) . The breadth of the river is

When a stone falling from the top of vertical tower has fallen a distance xm,another is let fall from a point y m below the top .If the fall from rest and reach the ground together,then the height of the tower is

A tree breaks due to storm and the broken part bends so that the top of the tree touches the ground by making 30^(@) angle with the ground. The distance between the foot of the tree and the top of the tree on the ground is 6m. Find the height of the tree before falling down.

A tree breaks due to storm and the broken part bends so that the top of the tree touches the ground by making 30^@ angle with the ground. The distance between the foot of the tree and the top of the tree on the ground is 6 m. Find the height of the tree before falling down.