Final Exam Flashcards
When lifting a hand box or a barbell off the floor, which joint or body part, would you want to minimize torque Where would you want maximize torque
Minimize the flexion torque on the L5 -S1 to promote safety, maximize torque at the hip joint
The point around which a bodies weight is equally balance in all directions is known as what?
center of gravity
Is it easier to push or pull a desk across the classroom floor why?
Pull, you are reducing resistance by decreasing weight as opposed to pushing you are increasing resistance you are adding weight
The rotary effect of a force about an axis of rotation is known as what?
Torque/moment
What is a forced couple?
A pair of equal opposite forces
What is the difference between balance and stability?
Stability is a resistance to distribution of equilibrium, whereas balance is an ability to control equilibrium
What does newtons first law in angular kinetic state?
Rotating body will continue to turn about its axis of rotation, with constant angular momentum, unless an external eccentric force is exerted upon it
When we mentioned in class to increase stability
Increase mass, increase friction, increase size of support
How does kinetic energy and potential energy change during a project child in motion?
Ascension -potential energy increases, kinetic decreases
Apex - potential energy at its highest, kinetic equals zero
Descent - potential energy decreases, kinetic energy increases
Why is this carnival game with the ladder so difficult to win ?
Your body center of gravity has to be aligned with the letters center of gravity, which is a narrow straight line and that line will cause you to fall off the ladder
What is the difference between mass and weight?
Weight implies gravity
Why would it hurt more getting punched in the face closed fist with the force of 250 and compared to getting slapped open palms in the face in the same spot with the same amount of force?
More pressure with close fist due to less surface area (P=F/A)
First class lever
Force and resistance on opposite sites of axis of rotation
Second class lever
Force and resistance acting on the same side or resistance is closer to the axis of rotation
Third class, lever
Force arm closer to axis of rotation resistance, being further away
What is a mechanical advantage?
Is a measure of the force amplification achieved by using a tool
Mechanical advantage = force/resistance
How does the patella increase mechanic advantage?
Increases the forearm between tendon and axis of rotation
What is static equilibrium?
Emotionless state in which there is no net force or net torque acting
Balance method
The weight and vertical reaction force at the fulcrum must lie in the same way
Inertia (linear)
- An object or bodies characterize, but its resistance to changes and its current state of motion
- deals with mass
- The more mass body has the more inertia it’s going to happen
Angular inertia (rotation)
- Object, your body resistance to angular acceleration
- mass + distance is distributed from the axis of rotation
Moment of inertia
Some of the products of each particles mass and the radius of rotation for the particles squared
What is the radius of gyration ?
Distance from the axis of rotation to a point where the bodies mass could be concentrated without altering its rotational characteristics
What is angular momentum?
- Quantity of angular motion possessed by a body
- measured as the product of moment of inertia and angular velocity
What produces change in angular momentum?
Angular pulse changes in angular momentum equals to the product of torque and time interval over which the torque acts
