Rotational Quantities Review for Quiz
SHOW THE EQUATION USED IN EACH PROBLEM!
Name _______________________________
1. Using our TORQUE analysis solve this problem: a 250 Newton carton is placed 0.8
meters from a pivot point as shown below. Another carton (130 N) is placed on the
opposite side at 1.1 meters from the pivot. In order to balance the board, where should
the third carton (weight = 80 N) be placed?
250 N
0.8 m
80
N
?
1.1 m
130 N
Rotational Quantities Review for Quiz
2.
a. In the Olympics, the hammer throw uses a 7.257 kg ball at the end of a 1.22 meter
chain. Calculate the rotational inertia (“moment of inertia”) of the ball:
b. Find the rotational inertia (“moment of inertia”) of a
spinning basketball: consider it to be a hollow sphere,
with a mass of 0.600 kg and a radius of 0.121 meters.
‘Discrete’ mass: I = mr2
Hollow disk or ring: I = mr2
Solid disk or cylinder: I = ½ mr2
Hollow sphere: I = (2/3) mr2
Solid sphere: I = (2/5) mr2
Rotational Quantities Review for Quiz
3. A space satellite with a mass of 247 kilograms
rotates at a rate of 12.4 radians/sec. It can be
roughly approximated to be a solid cylinder
with a radius of 2.2 meters.
a. What is the initial Moment of Inertia (Ii)?
b. If a meteorite hits it and it loses 58 kilograms of fuel, what will be the final
Moment of Inertia (If)?
c. Determine its new rotation rate using the Conservation of Angular Momentum.