- #1
paul_harris77
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I am slightly confused about an experiment to demonstrate centripetal force.
Suppose a tennis ball is attached to a piece of string. On the other end of the string is attached a mass hanger and some small masses. In the middle of the string is a small piece of plastic tubing. A person holds the string on the plastic tubing and starts swinging the ball around in a horizontal circle. As the ball speeds up, the mass hanger starts rising through the tubing. I am told that this is just due to the equation F=m(v^2)/r and that the radius must increase if the speed increases and the mass (source of the centripetal force) is staying constant. But surely an upwards force must be acting on the mass hanger through the string to cause the masses to rise? If so, wouldn't this be a centrifugal force? There lies the problem because I am told there is no such thing as a centrifugal force.
Thanks
Paul
Suppose a tennis ball is attached to a piece of string. On the other end of the string is attached a mass hanger and some small masses. In the middle of the string is a small piece of plastic tubing. A person holds the string on the plastic tubing and starts swinging the ball around in a horizontal circle. As the ball speeds up, the mass hanger starts rising through the tubing. I am told that this is just due to the equation F=m(v^2)/r and that the radius must increase if the speed increases and the mass (source of the centripetal force) is staying constant. But surely an upwards force must be acting on the mass hanger through the string to cause the masses to rise? If so, wouldn't this be a centrifugal force? There lies the problem because I am told there is no such thing as a centrifugal force.
Thanks
Paul