Why are objects that fall near Earth's surface rarely in free fall?
1 answer:
Answer: Air exerts forces on falling objects near Earth's surface.
Explanation: Objects falling near the earth surface are rarely in free fall due to the force exerted by air on falling object near the earth( air resistance).
The acceleration of free fall tend to pull the body towards the earth surface while air resistance (drag) tends to act in the opposite direction.
Given that the weight of the body is always constant.
The drag acts in the upward direction, thereby negating the downward weight of the object.
From Newton's Second law:
Force = mass × acceleration due to gravity
Acceleration = force / mass
The net force acting on the object becomes :
(Downward weight - upward drag)
This hampers the free fall of the object due to gravity.
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and vertical acceleration
downward. The two equations which gives the horizontal and vertical position of the salmon at time t are
(1)
(2)
We can solve the problem by requiring Sx=3.16 m and Sy=0.379 m, the data of the problem.
Solving eq.(1) for t:
And substituting this expression of t into eq.(2), we get the following expression for :
And substituting the numbers into the equation, we find