Let a small solid sphere of radius r, fall through a viscous liquid in a tall jar. Let v be the terminal velocity acquired by the sphere. The force acting on the sphere is,
1. The downward force due to the weight of the ball is given by mg
2. The upward force due to the viscous resistance is given by 6πηrv
3. The upward thrust exerted on the sphere by the liquid. It is equal to the weight of the liquid displaced by the sphere ma.
When the upward thrust balances the downward force, the ball attains constant velocity and this velocity is called terminal velocity.
6πηrv + ma = mg
ma = mg - 6πηrv
a = g - 6πηrv / m
No comments:
Post a Comment