The 4 Forces?

Question

Pretend the "O" is a ball what four forces would be attacking upon it? from both sides and vertically.


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Answer 1

If the ball is falling and there is a wind blowing from the left:
1) Weight acts downward
2) Air resistance (drag) acts upward
3) Wind force acts from the left
4) Air resistance acts from the right

If the ball is in rotation, then there will be a lift force which is generated because of pressure differences on each side. This is actually very complicated since it has to do with laminar and turbulent boundary layers and boundary layer separation.

Answer 2

Assuming the ball has mass and is in a gravity field, there are only two vertical forces: its weight, which is the force of gravity, and the counteracting force that keeps the ball from accelerating downward. This stems from f = ma; where a = f/m and f is the net force on the ball, m is its mass, and a = 0, which is its acceleration.

As the ball is just sitting there, there is no net vertical force f; so the weight of the ball and the counteracting force, which could come from the desk top the ball is sitting on, sum up to zero. That is f = W - F = 0; so that W = F where F is the equal but opposite force to the ball's weight.

Similarly for the horizontal forces, if there are any. They, too, whatever they might be, add up to zero. But there is no reason to believe there are any horizontal forces. The ball might very well be resting there without horizontal forces. This comes from Newton's first law, which says in part that an object at rest will stay at rest unless acted on by a net force.

Answer 3

If the ball in a free body diagram, is a free falling body, then obviously the downward force is pull of gravity, and the upward force is a retarding force, in other words air friction, if due to pressure difference, wind becomes observable, then the wind or molecules in air gives forces horizontally from both sides