Reading Guide Chapter 7 – Rotational Motion
7.1 The rotation of a Rigid Body
1. A rigid body is an object whose __________________ and __________________ do not change
2. The three basic types of motion of a rigid body are:
3. Why does every point on a rotating body have the same angular velocity?
4. What is the formula that relates linear velocity to angular velocity?
5. So two points of a rotating object will have different _____________ if they have different _____________ from the
axis of rotation, but all points have the same ________________________
6. What is the formula and units for angular acceleration?
7. List the corresponding angular formula for the following linear formulas
𝑑
V= 𝑡
_______________
d = vit + ½ at2
a=
𝑣𝑓−𝑣𝑖
𝑡
8. What is the relationship between the tangential and angular acceleration
Do Stop to think 7.1
7.2 Torque
9. What three things does a force depend on to cause a rotation or a twisting motion?
10. What is torque the equivalent of?
11. Define radial line
12. Forces that are parallel to the radial line has ________ effect on the wrench’s rotation, and thus contributes
_________________ to the torque
13. Only forces that are perpendicular ___________ to cause rotation
14. The formula for torque is _____________
15. How does the formula change if the force is directed at an angle?
16. How is torque different from force?
17. Torques are calculated about a ______________, ____________ or _______________
18. What is the moment arm?
19. When is torque positive? When is it negative?
Do stop to think 7.2
Net Torque
20. How is net torque determined?
Do stop to think 7.3
7.3 Gravitational Torque and the center of gravity
21. How can the center of gravity be found?
22. Find the tactics box for calculating the center of gravity and write down the four steps
Do stop to think 7.4
7.4 Rotational Dynamics and Moment of Inertia
23. What does torque do?
24. How can the moment of inertia be determined for a collection of particles?
25. Newton’s second law can be rewritten for rotation. State Newton’s 2nd law for rotation
26. What happens to an object when net torque is zero?
27. Give the rotational variable that corresponds to the following linear variables
Fnet
m
A
Fnet=ma
Do stop to think 7.5
7.6 Rolling Motion
28. Rolling Motion combines two motions – what are they?
29. What point on a rolling object is instantaneously always at rest? ______________
30. What is meant by rolling without slipping?
Do stop to think 7.6