Quiz #3 Flashcards
Is TORQUE linear or angular?
Angular
Is MOMENT INERTIA linear or angular?
Angular
Is ANGULAR MOMENTUM linear or angular?
Angular
Is ANGULAR DISPLACEMENT linear or angular?
Angular
Is ANGULAR VELOCITY linear or angular?
Angular
Is TANGENTIAL VELOCITY linear or angular?
Linear
Is ANGULAR ACCELERATION linear or angular?
Angular
Is TANGENTIAL ACCELERATION linear or angular?
Linear
Is CENTRIPETAL ACCELERATION linear or angular?
Linear
Is TORQUE kinetic or kinematic?
Kinetic
Is MOMENT OF INERTIA kinetic or kinematic?
Kinetic
Is ANGULAR MOMENTUM kinetic or kinematic?
Kinetic
Is ANGULAR DISPLACEMENT kinetic or kinematic?
Kinematic
Is ANGULAR VELOCITY kinetic or kinematic?
Kinematic
Is TANGENTIAL VELOCITY kinetic or kinematic?
Kinematic
Is ANGULAR ACCELERATION kinetic or kinematic?
Kinematic
Is TANGENTIAL ACCELERATION kinetic or kinematic?
Kinematic
Is CENTRIPETAL ACCELERATION kinetic or kinematic?
Kinematic
Equation for TORQUE:
T= F(r)
*r in this case is moment arm
Equation for MOMENT OF INERTIA:
I = mr^2
Equation for ANGULAR MOMENTUM:
H = I (ω)
Equation for ANGULAR DISPLACEMENT:
Δθ = Δ angular position
Δθ = θf - θi
Equation for ANGULAR VELOCITY:
ω = Δθ/ Δtime
Equation for TANGENTIAL VELOCITY:
Vt= ω(r)
Equation for ANGULAR ACCELERATION:
α = Δω/ Δtime
Equation for TANGENTIAL ACCELERATION:
αt = α(r)
Equation for CENTRIPETAL ACCELERATION:
αr = Vt^2/r αr = ω^2r
Units for TORQUE:
Nm
Units for MOMENT OF INERTIA:
kg*m2
Units for ANGULAR MOMENTUM:
kg*m2 /s
Units for ANGULAR DISPLACEMENT:
rads
Units for ANGULAR VELOCITY:
rad/s
Units for TANGENTIAL VELOCITY:
m/s
Units for ANGULAR ACCELERATION:
rad/s2
Units for TANGENTIAL ACCELERATION:
m/s2
Units for CENTRIPETAL ACCELERATION:
m/s2
Is ANGULAR IMPULSE linear of angular?
Angular
Equation for ANGULAR IMPULSE:
ΣTΔt
Units for ANGULAR IMPULSE:
Nm*s
Difference between an absolute and relative angular position:
Absolute- other line or plane is fixed and immovable relative to the earth
Relative- other line or plane is capable of moving
Relationship between tangential velocity and average angular velocity, and how the relationship applies to sports:
VT = W(r)
Tangential velocity is equal to angular velocity times the radius.
Swinging a baseball bat. The further that the bat hits the ball from the axis of rotation, the faster it will be hit.
Increase in radius, but keep the angular velocity the same, there will be an increase in linear velocity.
Define moment arm:
Perpendicular distance between the line of action of the force and a line parallel to it that passes though the axis of rotation
How does moment arm affect torque?
Moment arm can change throughout movement, but radius does not change.
If force is held constant and moment arm increases, torque increases
If force is held constant and moment arm decreases, torque decreases
What is the center of gravity, and what affects it?
Point in a body or system around which its weight is evenly distributed or balanced and through which the force of gravity acts
Gender; top heavy/bottom heavy →skip leg day
What affects stability?
Increase base of support/contact
Widen stance
Lower to ground
Relationship between angular impulse and angular momentum.
Conservation of Angular Momentum: Hi = Hf IiWi = IfWf
Angular Impulse: T(t) = ΔH
Why is it easier to hit a golf ball further with a driver (the longest club) than a pitching wedge (the shortest club)?
The radius is longer in the driver.
VT = ω(r)
What advantages do longer limbed individuals have in throwing or striking activities?
Increase in radius will increase the tangential velocity, causing it to go further (if angular velocity is kept constant)
Why is it recommended that you flex your knees and hips (squat down) when lifting a heavy load off the floor, rather than just flexing your hips and back (leaning over)?
Flex just at hips/back, the moment arm just on hips is shorter and back is greater, which increases torque on the back/hips.
Flex just at hips/knee, the moment arm just on hips and knee is greater, which increases the torque on the back/hips. Some of the torque is distributed between the hips and knees.
Which exercise is easier to do (if you use the same weight for both), a straight-arm pullover, or a bent-arm pullover?
Bent-arm because moment arm about the shoulder is smaller, decreasing the amount of torque
Arms completely straight is much harder because moment arm is longer, increasing torque
Describe the best position to be in when you compete in a tug-of-war competition.
Increased stability: low to ground, staggered stance, and leaning back
When thinking of skills that require spinning, why is it beneficial for a gymnast to be smaller?
I=mr2
Rotating about a smaller radius, smaller mass, which means you have a smaller moment of inertia. Smaller moment of inertia means you are less resistant to changes in angular motion → spin easier
Centric motion and type of movements:
Pushing through center of gravity → causes linear movement
Eccentric motion and type of movements:
Not through center of gravity → linear and angular movement
Force couples and type of movements:
Opposing motions → causes angular movements
