PHYSICS 5A Lecture 11: Physics 5a_ Lecture 11_ Uniform Circular Motion

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orangemole240

22 Apr 2018

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Suppose something is rotating at f = 1hz; then that object has an angular velocity of 2 hz. Remember from before that the speed of an object moving in a circle if v = 2 rf, and we can get. V = r (using the above equation) For an object moving in a circle this says that the object"s speed is proportional to the radius of the circle and the object"s angular velocity. Note that stands for omega: the angular frequency or angular speed (measure in radians) Example of bug sitting on a rotating disk. A disk rotates 2 times per second. A bug of mass 0. 001 kg sits on disk at a radius of 20 cm. The force on the bug to keep it rotating around on disk is the centripetal force. Example: car making circular turn & maximum walking speed.

Related Questions

hi,

i have 5 questions i need the

complete solutions with their final results. is there anyonecouldhelp

me, i would appreciate that.

1)

Consider a point on a bicycle wheel as the wheel turns about afixedaxis, neither speeding up nor slowing down. Compare thelinear andangular velocities of the point.

2)
A point on the rim of a 0.25-m-radius rotating wheel hasacentripetal acceleration of 4.0 m/s2. What is the angular speedofthe wheel?

3)
A point on the rim of a 0.15-m-radius rotating disk hasacentripetal acceleration of 5.0 m/s2. What is the angular speedofa point 0.075 m from the center of the disk?

4)
A 0.150-m-radius grinding wheel, starting at rest, developsanangular speed of 12.0 rad/s in a time interval of 4.00 s. Whatisthe centripetal acceleration of a point 0.100 m from thecenterwhen the wheel is moving at an angular speed of 12.0rad/s?

5)

What centripetal force does an 80-kg passenger experiencewhenseated 12 m from the center of a Ferris wheel whose angularspeedis 0.50 rad/s?

thank you in advance

An object of mass M= 2.00 kg. is attached to a spring with springconstant k= 198 N/m whose unstretched length is L= 0.200 m., andwhose far end is fixed to a shaft that is rotating with an angularspeed of

Ï = 3.00 radians/s . Neglect gravity and assume that the mass alsorotates with an angular speed of 3.00 radians/s as shown. (Intro 1figure)

When solving this problem use an inertial coordinate system, asdrawn here. (Intro 2 figure)

Given the angular speed of Ï = 3.00 radians/s , find the radiusR(Ï) at which the mass rotates without moving toward or awayfrom the origin.

Express your answer in meters.

An object of mass M is attached to a spring with spring constant k whose unstretched length is L, and whose far end is fixed to a shaft that is rotating with an angular speed of ω. Neglect gravity and assume that the mass also rotates with an angular speed of ω as shown. (Figure 1)When solving this problem use an inertial coordinate system, as drawn here. (Figure 2)

1) Given the angular speed of ω , find the radius R(ω) at which the mass rotates without moving toward or away from the origin.

2) Assume that, at a certain angular speed ω2, the radius R becomes twice L. Find ω2.

Express your answer in radians per second.

3) You probably have noticed that, as you increase ω, there will be a value. ω_crit, for which R(ω) goes to infinity. Find ω_crit.