Rotation and Torque Test
Name ___________________________
Date __________
1. 0.3912 meters of thread is pulled off a spool whose radius is r = 0.0120 m
a. Through how many radians does it rotate?
b. How many degrees is that?
2. A 4.50 m radius merry-go-round is spinning at 0..785 rad/sec.
a. What tangent (linear) speed is this at the outermost edge of the merry-goround?
b. What tangent speed is this ½ way out on the merry-go-round?
Rotation and Torque Test
3. A dentist drill starts from rest and reaches 60,000 RPM in 1.55 sec.
a. Convert 60,000 RPM into radians/sec
b. Find its angular acceleration, :
c. Find the tangent (linear) acceleration, a, if the drill radius is 1.00 x 10-3 m.
4. Conan the Barbarian rotates an enormous
wheel. Let’s say it has a mass of 3.30 x
103 kg and a radius of 5.00 meters. Conan
is pushing on the wood lever at a distance
of 6.00 meters from the center. How
much force would he have to exert to start
the wheel rotating from rest to 0.175
rad/sec in 7.00 sec?
(We are ignoring frictional effects, which
are undoubtedly substantial, and consider
only the inertia of the large cylindrical wheel)
If you can’t turn this
you’re a girly man…
Rotation and Torque Test
5. A 5.00 kg mass is hanging from a 10.0 kg pulley with a radius of 0.360 m. Find
the (tangent, or linear) acceleration, a, of the mass as it falls.
(Show all work! Yes, right from the beginning…free body
10.0 kg
diagrams, the whole works; neatly).
5.00 kg
Rotation and Torque Test
6. Competing torques: Use Newton’s 2nd Law (Rotation form) to find the force with
which the 2.00 kg mass is being pulled upward if the angular acceleration () =
21 rad/sec2. The pulley can be considered a solid disk
and has a mass of 1.50 kg and a radius of 0.500 meters.
?
2.00
kg