Name:___________________
Ch 8 Study Guide: Rotational Motion
1. Angles may be measured in degrees or in _________.
2. 1 revolution is equal to _______ degrees which is equal to ______ rad.
3. Perform the following conversions:
a.
2 revolutions into rad
b.
80ْ into rads
c. 4.2 revolutions into rad
d. 38 rad/s into revolutions per min (rpm)
4. ω is the symbol for ____________. It’s equivalent in linear motion is _____.
5.
To calculate ω the formula is…
6.
Label the two arrows on the picture above and explain what they represent.
7. Fill in the missing information in the box below.
8. There are parallels between translational motion and rotational, and many of the equations are virtually
the same. Given the formulas below fill in the missing equations to complete the table.
9. The moment of force about the axis is more commonly called ________________. It is calculated with the
equation
. Each letter of the equation stands for…
10. Newton’s second law has many applications in physics. For rotation Newton’s second law is…
11. Each symbol of this formula represents…
12. An object rotating about an axis has rotational ____________ ____________. The equivalent equation for
translational motion is equal to 1/2mv2. The Rotational equation is…
13. Just as linear momentum is conserved so is it for rotational. This concept is called:
14. Angular acceleration is identified with the Greek symbol ______ and is calculated using the formula:
15. When a fan performing 10 revolutions per second is switched off, it comes to rest
after 10 seconds. Calculate the average angular acceleration of the fan after it was
switched off. (Hint: don’t forget to convert revolutions into the necessary units!)
16. When a machine is switched on, the angular velocity of the motor increases by 10 rad/s for the first 10
seconds before it starts rotating with full speed. What is the angular acceleration of the machine in the
first 10 seconds?
17. For a given applied force, the change in angular velocity depends on the _____________, which is the
perpendicular distance from the axis of rotation to the point where the force is exerted.
18. A bolt on a car engine needs to be tightened with a torque of 35 m·N. You use a wrench with a lever
arm of 22cm and pull on the end of the wrench at an angle of 60.0° from the perpendicular. How much
force do you have to exert?
19. Fill in information in the boxes below to complete the table.
20. If a truck has a linear acceleration of 1.85 m/s2 and the wheels have an angular acceleration of 5.23 rad/s2 what is
the diameter of the truck’s wheels?
21. The ball in a computer mass is 2.0 cm in diameter. If you move the mouse 12 cm, what is the angular
displacement of the ball?
22. If a torque of 55.0 m·N is required and the largest force that can be exerted by you is 135 N, what is the length
of the lever arm that must be used?