AH Exp – Mechanics 03B – Central force and angular velocity

Aim – To investigate the relationship between the central force maintaining the circular motion of a ball and the angular velocity of the ball.

Instructions

The apparatus is set so that the masses rest on an elastic band in the centre of the turntable.
As the turntable rotates, the central force required to maintain the circular motion of the ball is provided by the weight of the masses.
When the turntable is started, it increases in speed and the central force required to maintain the circular motion increases to the point at which the masses just lift off the elastic band.

▪ Start the turntable rotating and allow it to increase in speed until the ball just starts to move outwards. At this point the masses just lift off the elastic band. (This may take several revolutions)
▪ Use a stopwatch to measure the period of the ball.
▪ Determine the angular velocity of the ball.
▪ Repeat for different masses.
▪ Draw a graph to show the relationship between the central force and the angular velocity.

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