Question

A coin of mass 3.68 grams is placed on a record turning at 33 1/3 rpm (revolutions per minute). What is the speed of the coin when it is placed 10.3 centimeters and 17.8 centimeters from the center of the record? Include units in your answers. What is the acceleration of the coin at those locations? Include units in your answers. What net force must act on the coin at those locations to keep it on the record? Include units in your answers. All answers must be in 3 significant digits.

Answer 1

b. In order to determine the speed of the coin, use the following formula:

$v=\omega r=\frac{2\pi}{T}\cdot r$

where,

T: period = 1.80s

r: distance of the coin to the center of the record = 10.3 cm, 17.8 cm

Replace the previous values of the parameters into the formula for v and simplify:

c. The acceleration of the coin is given by:

$a=\frac{v^2}{r}$

Then, by replacing the values of v and r, you obtain:

d. In this case, the force is about the centripetal force, which is given by:

$F=ma$

By using the previous results, you obtain: