Vivian L. answered • 03/04/14

Tutor

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Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACH

Hi Meg;

*A. What is the period of rotation?*

This is the amount of time required for one rotation...

(600 seconds)/(20 revolutions)

(30 seconds)/(1 revolution)

Period of rotation is 30 seconds.

*B. What is the velocity if the object is 14 cm from the center of rotation?*The circumference of the rotation is...

(3.14)(2r)

3.14 is, of course, pi.

r is, of course, the radius.

(3.14)(2)(14 cm)

^{}(3.14)(28 cm)

87.92 cm

In round figures, this is 90 cm.

distance=(velocity)(time)

s=vt

90 centimeters=(velocity)(30 seconds)

(90 centimeters)/(30 seconds)=velocity

3 centimeters/second=velocity

*C. What is the centripetal force on a 35 g mass spinning 14 cm from the center of rotation?*

force=m(v

^{2}/r)force=(35 g)[(3 cm/s)

^{2}/(14 cm)]force=(35 g)[(9 cm

^{2}/s^{2})/(14 cm)]Let's note that the unit of cm

^{1}is in the numerator and denominator. It cancels...force=(35g)[(9 cm/s

^{2})/(14)]force=22.5 g-cm/s

^{2}