Download presentation

Presentation is loading. Please wait.

Published byLuke Summerfield Modified over 2 years ago

1
ANNOUNCEMENTS Lab make-up : Labs 1 - 3. - at least 5 labs are required to pass the course; - contact your TA to arrange lab makeup ahead of time. You will need to attend twice: (1) for lab make-up; and (2) for review recitation. You can attend any other section (in addition to your regular section), with that section’s TA advance permission. Read Chapter 8. CAPA assignment #10 is due Friday at 10 PM. Recitation Review 1: required. Chs. 1-7. Print & bring to class.

2
Rotational Motion NII for rotations Conservation of angular momentum Conservation of mechanical energy Motion of a “rigid” body about a fixed axis of rotation.

3
Rotational Motion polar coordinates angle of rotation (rads) Motion of a “rigid” body about a fixed axis of rotation.

4
Rotational Motion angular velocity (rad/s) Motion of a “rigid” body about a fixed axis of rotation.

5
Rotational Motion angular acceleration (rad/s 2 ) Motion of a “rigid” body about a fixed axis of rotation.

6
Rotational Kinematics Remember: s = r θ (r,θ) polar coordinates For circular motion, θ completely describes the motion. It gives the “rotational position”. (θ: rads) Circumference: C = 2πr 360° = 2π rad 180° = π rad 57.3° = 1 rad

7
s = r θ tangential velocity (m/s) arc-length formula use arc-length formula r = const for circular motion define: angular velocity ω Δs Rate at which θ is changing Rotational Kinematics

8
A pocket watch and Big Ben are both keeping perfect time. Which minute hand has larger angular velocity ω? A)Pocket watch. B)Big Ben. C)Same ω. Clicker QuestionRoom Frequency BA

9
A pocket watch and Big Ben are both keeping perfect time. Which minute hand’s tip has larger tangential velocity v? A)Pocket watch. B)Big Ben. C)Same v. v = rω Clicker QuestionRoom Frequency BA

10
A small wheel and a large wheel are connected by a belt. The small wheel turns at a constant angular velocity ω S. There is a bug S on the rim of the small wheel and a bug L on the rim of the big wheel. How do their speeds compare? A)v S = v L B)v S > v L C)v S < v L Clicker QuestionRoom Frequency BA

11
A small wheel and a large wheel are connected by a belt. The small wheel turns at a constant angular velocity ω S. How does the magnitude of the angular velocity of the large wheel ω L compare to that of the small wheel ω S ? A)ω S = ω L B)ω S > ω L C)ω S < ω L Clicker QuestionRoom Frequency BA

12
s = r θ arc-length formula Δs angular velocity Units : Note: rpm = 60 f = 60/τ Rotational Kinematics

13
s = r θ arc-length formula Δs Rate at which θ is changing tangential acceleration (m/s 2 ) use equation for ω r = const for circular motion define: angular acceleration α Rate at which ω is changing

14
A ladybug is clinging to the rim of a wheel spinning CCW. Assuming that the wheel is spinning at a constant rate, what is the direction of her acceleration when she’s at the far right? Since her speed is constant, a tan = 0, so the only acceleration is centripetal acceleration pointing toward the center of the wheel. Clicker QuestionRoom Frequency BA

15
A ladybug is clinging to the rim of a wheel spinning CCW. Assuming that the wheel is speeding up, what is the direction of her acceleration when she’s at the far right? v 2 > v 1 Clicker QuestionRoom Frequency BA

16
A vinyl record has radius r = 6 in = 15.2 cm and spins at 33.3 rpm (revolutions per minute). What is its period? A)33.3 secB) 3 sec C) 1.8 secD) 0.55 sec s = r θ Clicker QuestionRoom Frequency BA

17
A vinyl record has radius r = 6 in = 15.2 cm and spins at 33.3 rpm (revolutions per minute). 1. What is its period? 2. What is its frequency? A)33.3 HzB) 3 Hz C) 1.8 HzD) 0.55 Hz s = r θ Clicker QuestionRoom Frequency BA

18
A vinyl record has radius r = 6 in = 15.2 cm and spins at 33.3 rpm (revolutions per minute). 1. What is its period? 2. What is its frequency? 3. What is its angular velocity? A)0.55 HzB) 3.49 rad/sec C) 1.8 rad/sec D) 0.88 rad/sec s = r θ Clicker QuestionRoom Frequency BA

19
A vinyl record has radius r = 6 in = 15.2 cm and spins at 33.3 rpm (revolutions per minute). 1. What is its period? 2. What is its frequency? 3. What is its angular velocity? 4. What is the speed v of a bug on its rim? A)53 cm/sec B) 3.49 cm/sec C) 4.35 cm/sec D) 8.44 cm/sec s = r θ Clicker QuestionRoom Frequency BA

20
A vinyl record has radius r = 6 in = 15.2 cm and spins at 33.3 rpm (revolutions per minute). 1. What is its period? 2. What is its frequency? 3. What is its angular velocity? 4. What is the speed v of a bug on its rim? 5. What is the magnitude of the acceleration of the bug? A) 184 cm/s 2 B) 103 cm/s 2 C) 53 cm/s 2 D) 0 cm/s 2 s = r θ Clicker QuestionRoom Frequency BA

Similar presentations

OK

Circular Motion. Position on a Circle Motion in a circle is common. The most important measure is the radius ( r ). The position of a point on the.

Circular Motion. Position on a Circle Motion in a circle is common. The most important measure is the radius ( r ). The position of a point on the.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on centring concrete Ppt on cross border merger and acquisition Ppt on world trade organisation Marketing mix ppt on nokia phone Ppt on waxes definition Ppt on ufo and aliens are they real Ppt on p&g products images Ppt on area of parallelogram and triangles and quadrilaterals Ppt on online trading of shares Ppt on media in hindi