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Physics Help Please!!! All multiple choice!

1.) Does an object moving in uniform circular motion have constant centripetal acceleration?
True or False

2.) How do the angular velocities of three knots on a rope compare as it is swung around in a circle? How about their speeds?

a.) the angular velocity and linear velocities are the same

b.) the linear velocities are the same, the angular velocity increases as you move toward the outside dot

c.) the angular velocity is the same, the linear velocities are fastest in the center

d.) the angular velocity is the same, the linear velocities are fastest on the outside

e.) both the linear and angular velocities increase as you move out



3.) An object travels with a constant speed in a circular path. The net force on the object is

a.) zero

b.) toward the center

c.) away from the center

d.) tangent to the object's path

Respuesta :

skyluke89
1) True. 
Uniform circular motion means that the angular velocity [tex]\omega[/tex] is constant, and since the centripetal acceleration is given by
[tex]a=\omega ^2 r[/tex]
if [tex]\omega [/tex] is constant, then a is constant.

2) The correct answer is
a.) the angular velocity and linear velocities are the same
The three knots are in fact on a circle, therefore the angular velocities are the same (because they cover the same angle in the same time) and the linear velocities are the same as well, because it is given by
[tex]v=r \omega[/tex]
and since both r(distance from the center) and [tex]\omega[/tex] are the same, v is also the same.

3) b.) toward the center
In fact, an object can move on a circular path only if there is a force pushing towards the center. This force is called "centripetal force".