4. Allow Sad, But Do not Despair Circular motion is the motion of objects on the circular trajectory, speed of object speed and direction remain changeable. Circular motion can be divided into: Uniform circular motion (GMB) Circular motion uniformly accelerated (GMBB)
5. Allow Sad, But Do not Despair Uniform Circular Motion Objects moving in a circle is said irregular if the object is moving with constant angular velocity on a circular trajectory The position angle can be calculated by the equation: = ω. T, with t = time (s) Angular position versus time graph on the GMB: t
6. Allow Sad, But Do not Despair MAGNITUDES IN CIRCULAR MOTION PERIOD (T): time needed by the body to take the path to a full circle. Where is the second unit (s). T = 1/f FREQUENCY (f): Number of walks taken a full circle objects in one second. Where is the Hertz unit (Hz). f = 1/T
7. Allow Sad, But Do not Despair LINEAR VELOCITY (v): The distance traveled divided by the object latency V = 2 Л r / T V = speed of the linear (m /s) r = radius of the circle T = period (second) A v
8. Allow Sad, But Do not Despair ANGULAR VELOCITY (ω): The angles that have been taken within a certain time interval ω = 2 Л /T With ω = angular velocity (rad / s) T = period (s)
9. Allow Sad, But Do not Despair Example Problem: Bakri spur bike on a circular trajectory within 1 hour. In that time, Bakri has done 120 laps. Determine the period, frequency, kecepatn linear and angular velocity Bakri if the track has a diameter of 800 m!
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13. Allow Sad, But Do not Despair Example Problem : Bambang riding a motorcycle through a bend circle 20 m fingered finger when going to school. If Bambang motor speed 10 m / s, determine the acceleration Bambang trajectory leading to the center! Unknown : Asked : a s = .....? Answer : a s = v 2 /r =(10) 2 /20
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17. Allow Sad, But Do not Despair Relations Wheels a. Concentric relationship: On the relationship of two concentric wheels direction of rotation and angular velocity both same wheel. So: ω1 = ω2 b. relationships intersect In this connection both the direction of rotation linear speed of the two opposite and equal. So v1 = v2 c. Relationship of two wheels with a rope, then the direction of rotation and linear speed of the same. So v1 = v2
18. Allow Sad, But Do not Despair Look at pictures of the three wheels are in a relationship as follows: If Rc = 4 cm, 6 cm and Rb = Ra = 8cm, and the wheel angular velocity w = 8 rad / s. discussion: 1. a wheel angular velocity 2. wheel linear speed of c
19. Allow Sad, But Do not Despair Solution Given: Ra = 4 cm = 4x 10 -2 m Rb = 6 cm = 6x 10 -2 m Rc = 8 cm = 8x 10 -2 m ωb = 8 rad / s asked: 1. ωa 2. vc Answer: 1. va = vb ωaRa = ωc.Rc ωa. (4x 10 -2 ) = 8. (6x 10 -2 ) ωa = 12 rad / s. 2. ωa = ωc vc = ωa.Rc vc = 12. (8x 10 -2 ) vc = 0.96 m / s
