The motion of water in a dam serves human beings by generating electricity as it is a controlled motion. give one example for an uncontrolled motion. what effects could it cause

When the water flows in the dam or reservoir is not restricted or is impossible to restrict due to flood, earth quake or some other natural calamity, life is endangered both to human beings and animals as the water may pass through the forests and may even enter the cities and residential area when the limit is reached and the dam overflows.

Dam plays an vital roles on drinking water supply, flood control, electricity generation, fishing, tourism, etc. The creation of storage and head allow dams to generate electricity. Another situation is when the construction of the dam collapses due to structural failure or leaks.

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.