Help me undertsand?

Question

how does air friction change the motion of a ball or the velocity of a ball coming down a ramp which is attached to a counter top? please kindly be as detailed as possible when explaining this.

Thank you, any help will be greatly appreciated.

Answer 1

A ball rolling down a ramp is subject to three forces:

1) gravity, = Fg = m*g*cosø

2) rolling friction Fr = m*g*k*sinø (k = coeff of friction)

3) air friction Fa - K*v^2, v= ball velocity along ramp.

Both rolling friction and air friction will reduce the acceleration of the ball down the ramp. Because rolling friction is constant (independent of the ball motion), its effective result is to reduce the value of g. However, since air friction increases with velocity, there will reach a point where the air frictional force balances out the "net g" force on the ball. At this point the ball no longer accelerates, and reaches "terminal velocity".

Answer 2

A rolling ball is cutting through th surrounding air; air friction is then produced as a result of the resistance offered by the air. The result is to decrease the acceleration of the ball.

Answer 3

Technically, it's not really friction that's affecting the velocity. It's the energy transfer that occurs as the falling ball stirs the air through which it's traveling. Friction does play a role, but it's very very small.

It's like standing in the middle of a very large crowd of people that only want to stand in one spot and very close together. They're very stubborn people I suppose. The only way to get out of this crowd is to push people out of the way. You'll find that you can't run as fast as you want to because every time you contact someone to shove them out of the way, you slow down because energy is transferred from you to that person. A similar thing happens to the ball. It doesn't slowly rub against the air. It shoves the air out of its way, and that shoving takes energy.