In
circular speed a term that comes up a lot is uniform circular motion. Basically
this means that an object is traveling in a perfect circle at a constant speed. Notice
how I said speed NOT velocity. That is because as I said earlier velocity
is a vector meaning it would have to remain at the same speed and continue in the same direction. Since it is traveling in a circle it is constantly changing direction thus changing its velocity.
The
basic velocity formula can be used to determin the average velocity that an object is traveling in a circle.
The
circumference can be found using the formula
Circumference = 2*pi*radius
Combining these formulas will give us a
new on that can be used but the time will be the time for the object to make one complete revolution around the circle (period)
If
you analyze this formula you can see that that larger the radius the higher the speed will be.
So if you are on a merrygoround and you were to walk from the center towards the outside your speed would increase
as you walk out. An easy experiment can be done to show this. If you were to attach four LED lights to a string and then spin them in a circle it can be seen that the
light on the outside is spinning at a faster rate than that of the light closest to the center.
Since the lights are attached to the same
string and the same force is being applied to spin all the lights the lights on the outside need to spin faster in order to
cover the same amount of distance.
As I said earlier that you don’t have
a constant velocity in uniform circular motion. The velocity vector is always
tangent to the circle at any point on the circle. This and the concept of inertia
shows why on a merrygoround your body wants to fly off. If you were to have
an aerial view of someone letting go of the bar on a merrygoround you would see them fly off tangent to the point at
which they let go.
