Conservation of Momentum & Linear Kinetics Flashcards
What Is Momentum?
Quantity of motion that an object possess
What Is Linear Momentum?
Product of object’s mass and its velocity
What Is Angular Momentum
Product of objects moment of inertia and it’s angular velocity
What is the linear Momentum formula and units?
M=mv and kg* m/s
What is the angular Momentum formula and units?
H =Iw and kg*m^2/s
What Does “M” stand for
Momentum
What Does “m” stand for
mass
What does “H” stand for
Angular momentum
What does “I” stand for
Inertia
Race Car vs. full Garbage truck which one will go faster? and which one will have more mass?
Using the formula M=mv
Race car will go faster but the garbage truck has more mass
How do we change momentum?
Change mass and velocity
Linear momentum Is vector meaning?
Magnitude and direction
Collison Carts More mass means more _____ and an increase in _____.
More mass is causing more momentum increasing velocity
Conservation of Momentum is related to which one of Newton’s laws?
Law I
Newton’s Law : Linear 1 known as Law of intertia Says?
object at rest will stay at rest until a force is acted on
What Is Impulse?
External forces acting on an object change momentum
Impulse Is dependent on?
Time and Magnitude of force
Impulse formula Is
J=Ft
J for impulse formula Is
J = Impulse
F for impulse formula is
Force
t for impulse formula is
time
The relationship between Impulse and momentum Is related to which one of Newton’s Laws?
Law II
What Is Newton Law II : Law of acceleration
Object is proportional to and in the same direction as the force acting on it and to its mass
Is impulse Formula related to momentum?
F=ma
Changes In impulse may result from
Small force acting for long time and large force acting quickly
What Is the Hittaing a large force from the bat acting very quickly on the ball related with
Changes in momentum
Can we Manipulate impulse and How With a vertical jump
Increase time
which is not practical
Why is not practical to manipulate impulse for vertical jump
Because Force Decreases and time increases
Can we manipulate impulse? for landing
The difference between a Stiff landing and a soft
Stiff = a lot more force
soft = we can manipulate time
Angular Momentum Meaning
quantity of motion that an object possesses/ product of object’s moment of inertia and angular velocity
How do we manipulate angular momentum>
by changing Inertia or velocity
Increase inertia = decrease velocity
Decrease Inertia = increase velocity
H Is always constant what is H?
Angular Momentum
What are the three rotating bodies that pass through COM ( Center of mass) with angular Momentum?
Transverse , Frontal , and Longitundial
Transverse example is
Somersault
Frontal example is
Tilt
Longitudinal example is
Twist
A figure skater rotates with her arms out to her sides. In this position, her angular momentum is 20 kgm^2 / s, moment of inertia is 5kgm^2 and her angular velocity is 4 rad/s. if she crosses her arms over her chest, reducing her moment of inertia to 2kgm^2, what is her new angular velocity?
10 rad/s
For the figure skater example, how did we get 10 rad/s
H=Iw
20 = 5 x 4 =2
20/2 = 10
how do gymnasts initiate somersaults in the air? and how do they stop their rotations?
Starting position: Large inertia low velocity , we are just traveling up
Middle: tucked or pike : the distribution of mass Is increasing while inertia is decreasing and velocity is Increasing
.
End:When you are getting in the straight position to slow down , inertia is increasing and velocity is decreasing
Angular Momentum: gymnastic
While in the air the rotation is happening , Inertia is decreasing and angular velocity is increasing
What Is Contact Twist?
Only happens when in contact with the ground
What is Tilt
Only works when somersaulting , more tilt and faster twist
Contact Twist: generates what about what axis and what is an example and which of Newton’s laws is associated with it?
generates moment about longitudinal axis
example: turn shoulder during take off
Newton Law: II Law of reaction
to manipulate contact twist
manipulate rate of twist by pulling arms in to decrease inertia which results in increase in angular velocity
Long Jump angular Momentum: Long jumpers can have ___ kgm^2/s of angular ____ about what axis
15kgm^2/s
angular momentum
transverse axis
Manipulate jump/twist by exploiting ____ of Angular ___ or by what?
By exploiting conservation of angular momentum or by generating twist before take off
What Is kinetics
force that cause motion
What is more important Mass or distribution mass?
Distribution of mass
Force behind COM means
Forward
Force in front of COM
behinde
Force over COM means
straight
Newton laws : Linear Law I , II and III
- Inertia
- Acceleration
- Action-reaction
Heavier an object the acceleration will what?
Decrease
More mass of an object = More _____
More force to accelerate
Gravity accelerates bodies toward the center of the earth
at 9.81m/s^2
Ground reaction force: Horizontal
Decelerates
Mid-stance toe off Vertical ground Is ___.
Smaller
Horizontal ground forward as a runner does what to itself?
propels forward
Heel Strike the force is going ___ and the ground reaction is _____
Force = going forward
ground reaction going straight up
Moment of inertia
resistance and the greater the inertia the harder to move
The closer to the axis of rotation the further but
as far as the greater inertia it would be the object such as the the solid can
axis of rotation closer you are the less
Inertia
the further you are the greater
inertia
Skating the more you bring your arms in the less
inertia but you are spinning faster
Ice Skating, twisting gymnast you decrease what to increase _____ and vice versa
Decrease Inertia you increase angular velocity and increase inertia and decrease angular velocity
Moment of arm =
Distance from line of action of the force to axis of rotation
What are the two ways moment is calculated?
T=Ia
T= moment
I= moment of inertia
a = angular acceleration
And
T = Fd
T= Moment
F= force causing moment
d= moment arm of the force
Angular Newton’s Law II : Formula
T=Fd
whole body center of mass
Does not have to inside of the body weight becomes whole body
Somersaulting Is associated with which law and formula?
Law II and T=Fd
if force acts through the axis of rotation D and T would be
0
If the force is behind Its considered
somersault
if the force is in front it is considered
backflip