Question

In an experiment, a 0.028-kilogram rubber stopper is attached to one end of a string. A student whirls the stopper overhead in a horizontal circle with a radius of 1.0 meter. The stopper completes 10 revolutions in 10 seconds.
22. Determine the speed of the whirling stopper.

23. Calculate the magnitude of the centripetal force on the whirling stopper. [Show all work, including the equation and substitution with units.]

Answer 1

Hi there!

22.

We can calculate the speed by first calculating the period of the stopper.

1 period = time taken for one revolution

10 rev/10 sec = 1 rev/sec

Since it takes 1 second for the stopper to make a complete circle, its velocity can be found using the equation for circumference:

$v = \frac{2\pi r}{t} = \frac{2\pi (1)}{1} = \boxed{2\pi \approx 6.28 m/s}$

23.

The centripetal force can be solved for using the following:

$F_c = \frac{mv^2}{r}$

m = mass (kg)

v = velocity (m/s)

r = radius (m)

Fc = Centripetal force (N)

Plug in the givens:

$F_c = \frac{0.028(2\pi)^2}{1} = \boxed{1.105 N}$