Angular Kinematics UPDATED ACTUAL
Exam Questions and CORRECT Answers
Define angular inertia - CORRECT ANSWER - an object's resistance to change in angular
motion (newton's first law)
Angular inertia is also known as what? - CORRECT ANSWER - rotary inertia
What is moment of inertia - CORRECT ANSWER - quantity of angular inertia
What is moment of inertia dependent on? - CORRECT ANSWER - how the mass of an
object is distributed about the axis of rotation
What is the equation to find the moment of inertia? and define each variable - CORRECT
ANSWER - Ia = ∑ (mi ri^2)
- I = moment of inertia
- m = mass of particles
- r = radius or distance between particle and axis
When does the equation Ia = ∑ (mi ri^2) best used? - CORRECT ANSWER - When
applied to objects in which the distribution of mass is constant throughout the rotation
what are the units for moment of inertia? - CORRECT ANSWER - kg * m^2
T/F Mass alone contributes to angular inertia - CORRECT ANSWER -F
If the mass is ___ to the axis, then the resistance to change in angular motion is less and the
object will move ____ - CORRECT ANSWER - closer; faster
, The ____ the mass from the axis the greater the moment of inertia - CORRECT
ANSWER - further
Define gyration - CORRECT ANSWER - if an object gradually moves weight away from
the axis (distribution of mass changing as object rotates away from the axis)
The further the mass from the axis the MORE/LESS force needed to move it - CORRECT
ANSWER - MORE
What do divers do in order to complete as many flips as possible before hitting the water? -
CORRECT ANSWER - try to pull their mass as close to the axis of rotation as possible by
pulling their legs backward and to the side
When divers do the split tuck technique doe they have a large or small moment of inertia? -
CORRECT ANSWER - small because they have a shorter distance from their axis of
rotation. the goal is to increase velocity so they want a small resistance to angular motion
Does a gymnast on a bar have a large or small moment of inertia? - CORRECT
ANSWER - large because they are a greater distance from the axis of rotation (bar) and all
of their mass gets distributed to one side of the axis
Without changing the structure, how can one change the moment of inertia of a baseball bat? -
CORRECT ANSWER - choke up; decreases the moment of inertia so that the bat will
move faster
If a girl sits on a stool with her arms and legs extended and you spin her around, can you (she)
increase the angular velocity? - CORRECT ANSWER - Pull arms in to reduce the distance
between the mass of the person and the axis of rotation which makes the moment of inertia
smaller
Which a rubber tire or wooden tire accelerate equally down a slope? If not which one is faster? -
CORRECT ANSWER - NO. the wooden tire will accelerate faster because it has a smaller
moment of inertia.
Exam Questions and CORRECT Answers
Define angular inertia - CORRECT ANSWER - an object's resistance to change in angular
motion (newton's first law)
Angular inertia is also known as what? - CORRECT ANSWER - rotary inertia
What is moment of inertia - CORRECT ANSWER - quantity of angular inertia
What is moment of inertia dependent on? - CORRECT ANSWER - how the mass of an
object is distributed about the axis of rotation
What is the equation to find the moment of inertia? and define each variable - CORRECT
ANSWER - Ia = ∑ (mi ri^2)
- I = moment of inertia
- m = mass of particles
- r = radius or distance between particle and axis
When does the equation Ia = ∑ (mi ri^2) best used? - CORRECT ANSWER - When
applied to objects in which the distribution of mass is constant throughout the rotation
what are the units for moment of inertia? - CORRECT ANSWER - kg * m^2
T/F Mass alone contributes to angular inertia - CORRECT ANSWER -F
If the mass is ___ to the axis, then the resistance to change in angular motion is less and the
object will move ____ - CORRECT ANSWER - closer; faster
, The ____ the mass from the axis the greater the moment of inertia - CORRECT
ANSWER - further
Define gyration - CORRECT ANSWER - if an object gradually moves weight away from
the axis (distribution of mass changing as object rotates away from the axis)
The further the mass from the axis the MORE/LESS force needed to move it - CORRECT
ANSWER - MORE
What do divers do in order to complete as many flips as possible before hitting the water? -
CORRECT ANSWER - try to pull their mass as close to the axis of rotation as possible by
pulling their legs backward and to the side
When divers do the split tuck technique doe they have a large or small moment of inertia? -
CORRECT ANSWER - small because they have a shorter distance from their axis of
rotation. the goal is to increase velocity so they want a small resistance to angular motion
Does a gymnast on a bar have a large or small moment of inertia? - CORRECT
ANSWER - large because they are a greater distance from the axis of rotation (bar) and all
of their mass gets distributed to one side of the axis
Without changing the structure, how can one change the moment of inertia of a baseball bat? -
CORRECT ANSWER - choke up; decreases the moment of inertia so that the bat will
move faster
If a girl sits on a stool with her arms and legs extended and you spin her around, can you (she)
increase the angular velocity? - CORRECT ANSWER - Pull arms in to reduce the distance
between the mass of the person and the axis of rotation which makes the moment of inertia
smaller
Which a rubber tire or wooden tire accelerate equally down a slope? If not which one is faster? -
CORRECT ANSWER - NO. the wooden tire will accelerate faster because it has a smaller
moment of inertia.
