KIN 3309 1st Edition Final Exam Study Guide The final will consist of 50 MC questions 10 will be computation problems 5 will be MC bonus problems and the rest will be 35 MC problems At the bottom of this study guide all of the former quiz questions will be listed Lecture 13 March 23 Angular Kinematics deals with angular motion such as translation and rotation Nearly all human movement involves the rotation of body segments flexion extension lateral flexion abduction adduction Rotational Motion is when all parts of a body move through the same angle but do not undergo the same linear displacement General Motion is rotation and translation together Angles can be measured by degrees radians or revolutions We discussed two types of angles absolute angles and relative angles Absolute Angles are measured from an external frame of reference We can calculate them by using the arctangent function Relative Angles are angles formed between two limb segments We can calculate them in two ways by using the law of cosines if the segment lengths are known or calculate it from two absolute angles if they are known Lower Extremity Joint Angles are useful for clinicians to assess function and also useful for Biomechanists to quantify movement For the relative angle of the hip there is a positive angle for flexion and a negative angle for extension For the relative angle of the knee the angle is generally positive except for when hyperextended which will be negative For the relative angle of the ankle there is a positive angle for dorsiflexion and a negative angle for plantar flexion o Remember the rule of adding 90 degrees to this equation Angular Position Distance Displacement is analogous to linear distance and displacement Angular position is an object s position relative to a defined spatial reference system Angular distance is the length of the angular path taken along a path Angular displacement is the change in angular position and is a vector Angular Velocity and Acceleration Angular velocity is the rate of change of angular position and it indicates how fast the angle is changing A positive value indicates a counter clockwise rotation while a negative value indicates a clockwise rotation Angular Acceleration is the rate of change of angular velocity and this indicates how fast the angular velocity is changing Lecture 14 March 25 With Angular and Linear Motion the linear displacement can be determined when the length of the segment and the angular displacement are known With Angular and Linear Velocity the linear velocity can be determined when the length of the segment and the angular velocity are known With Tangential Velocity the direction of the linear velocity is tangent to the curved path You can maximize tangential velocity with a larger angular velocity and or larger radii With Centripetal Acceleration we are considering the acceleration towards the center of rotation Lecture 15 March 30 Kinematics vs Kinetics Kinematics examines spatial and temporal characteristics of motion with the forces causing the motion not being considered Kinetics deals with the cause of motion Sources of Forces There are different types of force that affect human movement One is the external environment such as gravity impacts ground reactions and fluid Another is the internal and biological mechanisms such as muscle contraction biomaterial properties and fluid air pressure We also talked about inertia affecting human movement Force Forces alter the motion and can change the shape of an object Forces are vectors in that they have both magnitude and direction They have points of application and lines of action and their unit is in Newtons Newton s Laws of Motion 1st Law Law of Inertia a body tends to stay at rest or in uniform motion unless acted upon by an unbalanced external force To initiate movement the external force must positively accelerate the object A greater mass equals greater inertia 2nd Law Law of Acceleration the change of motion of a body is proportional to the force impressed and is made in the direction of the straight line in which that force is impressed This is where the equation Force mass x acceleration comes into play 3rd Law Law of Action Reaction for every action there is an equal and opposite reaction on different objects Momentum is inertia mass in motion It is the tendency of an object to remain in motion Momentum mass x velocity and is a vector The Conservation of Momentum entails that in a system of bodies that exert forces on each other the total momentum in any direction remains constant unless some external force acts on the system in that direction Contact Forces include ground reaction force joint reaction force inertial force muscle force and elastic force Ground Reaction Force force exerted by the ground on a body in contact with it Joint Reaction Force the force experienced at a joint Inertial Force the force opposite in direction to an accelerating force acting on a body Muscle Force force when muscle fibers generate tension Elastic Force the tendency of solid materials to return to their original shape after being deformed Lecture 16 April 1 Free Body Diagrams are also called force diagrams and are used to analyze the forces and moments acting on a body They displace magnitude and direction Static and Dynamic Analysis static analysis concerns systems at rest or constant velocity while dynamic analysis concerns systems in motion Friction is the force acting parallel to the interface of two contacting surfaces during motion or impending motion The normal force is the force acting perpendicular to the surface The coefficient of friction is greater when an object is not moving Impulse An object with momentum can be stopped if a force is applied against it for a given amount of time It is the change in momentum and it is a vector Work Power Energy Work force x distance It is using a force to move an object a distance when both the force and the motion of the object are in the same direction Work is a scalar quantity Power work time or force x velocity It is the rate at which work is done Power is a scalar quantity Energy is the capacity of a physical system to perform work and can be either potential or kinetic or strain KE results from motion and PE results from position in gravitational field Energy is a scalar quantity SE is the capacity to do work due to deformation of a body Work Energy Theorem Conservation of Energy Work Energy Theorem The work done by a resultant