Forces, Mechanics and Biomechanics Flashcards
Define speed. What is it measuring? What is the S.I unit of speed? Is it a scalar or vector quantity?
It is a measurement of the distance an object travels over time, the S.I unit is m/s and it is a scalar quantity (no direction)
Define velocity. What is it measuring? What is the S.I unit of velocity? Is it a scalar or vector quantity?
It is a measurement of the distance an object travels over time in a specified direction, the S.I unit is m/s and it is a vector quantity (direction is included)
Define mass. What is it measuring? What is the S.I unit of mass? Is it a scalar or vector quantity?
It is a measurement of the quantity of matter in something, the S.I unit is kg and it is a scalar quantity (no direction)
Define weight. What is it measuring? What is the S.I unit of weight? Is it a scalar or vector quantity?
It is the downwards force an object exerts as a result of its mass and gravity acting upon it, the S.I unit is Newtons and it is a vector quantity (direction is included)
Define acceleration. What is it measuring? What is the S.I unit of acceleration? Is it a scalar or vector quantity?
It is the change in velocity over time, the S.I unit is m/s^2 and it is a vector quantity (direction is included)
What is full community ambulation?
The speed a person should be able to walk to safely navigate around the community (greater than 0.8m/s)
What is limited community ambulation?
The range of speed a person walks if they may have some trouble navigating safely around the community e.g. crossing pedestrian crossings fast enough (0.8-0.4 m/s)
What is household ambulation?
The speed a person walks if they are unable to safely navigate around the community (less than 0.4m/s)
In the absence of friction, what will the acceleration of a 1kg object be under 1N of force?
1 m/s^2
How much force can falling over onto your hip generate?
4000N (depending on person)
How much force would it require to fracture an osteoporotic hip in a fall?
2000N (depending on hip and fall)
What is friction?
The force that resists the movement of two objects moving in different directions while in contact/moving over each other.
What are the functions of articular cartilage?
Shock absorption and smooth joint movement
The lack of articular cartilage in a joint due to wear and tear is known as what?
Osteoarthritis, leading to pain and instability
What is Newton’s first law of motion?
Every object in a state of uniform motion tends to remain in that state until an external force is applied to it
What is Newton’s second law of motion?
The relationship between an object’s mass (m) and it’s acceleration (a) and the applied force (F) is F=ma, where the direction of the force and acceleration vectors are the same
What is Newton’s third law of motion?
With every action, there is an equal and opposite reaction
What is an object’s centre of gravity?
The equivalent point within an object at which the total weight of that object acts
What is an object’s base of support?
The area beneath an object or person that includes every point of contact that the object or person makes with the supporting surface
What are the common properties between all types of levers?
All levers involve a fulcrum, an effort force at a certain distance from the fulcrum and a load force at a certain distance from the fulcrum
What are the relative positions of the effort and load forces with relation to the fulcrum in a first order lever? What is an example of this form of lever?
The effort and load forces are on either side of the fulcrum like a seesaw
What are the relative positions of the effort and load forces with relation to the fulcrum in a second order lever? What is an example of this form of lever?
The load force is between the effort force and the fulcrum along the lever arm like a wheelbarrow or a foot pushing off the ground in a step
- Fulcrum = Metatarsals/toes
- Effort = Force of calf contraction via Achilles tendon
- Load = Body weight through shin bone and ankle joint
What are the relative positions of the effort and load forces with relation to the fulcrum in a third order lever? What is an example of this form of lever?
The effort force is between the load force and the fulcrum along the lever arm like a bicep
- Fulcrum = Elbow
- Effort = Bicep
- Load = Forearm, Hand and Whatever’s being carried
