What is Force (Biomechanics), External forces, and linear kinematics
curvilinear translation
direction of motion change although orientation of the object does not change
Displacement
displacement is the straight line distance in specific direction from initial to final postion.
velocity (rate of displacement)
displacement/ change in time
what can force do?
force can accelerate an object
Is force a vector quaunity?
force is a vector quanity
weight
force of gravity
concurrrent forces
forces that DO NOT act on the same line but do act on the same point.
External forces
forces that act on an object as a result of its interaction with the environment surrounding it. external force examples contact force, non contact force, friction, normal, gravity
Collinear forces
forces that have the same line of action
contact forces
forces that occur between objects in contact with each other
Sports excercise the only non contact force acts upon us is...
gravity
normal force (R)
is a force that is perpendicular to the surface that an object contacts.
ligament
is between bone to bone to keep structure.
Ground reaction force
is equal in magnitude and opposite in direction to the forces that the body exerts on the supporting surface through the object
what are three things about friction
is proportional to the normal force is independent of the size of surface size it is proportional to the roughness of surface area
rotary
motion in rotation
tendon
muscle bind to a bone
INTERNAL FORCES DO NOT!!!
produce any change in the motion in the motion of our body
Vector
size (magnitude) and direction (orentation)
which friction is greater static or kinetic
static is greater that kinetic
position
the location in space
ascending
time to maximum height
Force enables us to
walk, run, change direction, stand still.
Force of gravity acting on an object?
weight
descending
when the ball is falling before it hits the ground
Net force is ZERO
when the object is not moving because the normal force is equivalent to weight ( gravity). also the object is moving at a constant velocity.
Is displacement a vector?
yes
Net force a vector quantity
yes
acceleration (rate of change in velocity)
change in velocity/ change in time
Linear Kinematics
concerned with the description of linear motion
non contact force
Forces that act on an object without physically coming into contact with it.
Internal forces
Forces that actually within an object both tensile and compressive forces example body system structures such as organs, bones, muscles, tendons, ligaments cartilage etc..
In a horizontal motion of a projectile does the ball accerate horizontally while in the air does the ball speed up or slow down
No!!! its remains constant with its horizontally velocity and vertical acceleration.
Force equation: 1N equals
1kg mass x 1m/s2 or F= ma
how to calculate total time in projectile motion
2x maximum height
gravitational acceleration (g) equals
9.81 m/s2
Force
A push or a pull
Rectilinear translation
Direction of motion doesn't change
Speed (rate of Distance)
Distance/Change of time
How do we calculate friction?
F= uR
kinematics
The branch of dynamics (mechanics) concerned with the description of motion independent of force which cuase motion.
Friction force
The contact force that acts to oppose sliding motion between 2 surfaces
Net force
The sum of all forces acting on an object
can Force can come in pairs?
Yes force can come in pairs Action and reaction
what us a free body diagram used for?
a tool for analyzing forces and torques. a drawing to identify all external forces acting upon a object.with arrows showing an application and direction being applied on the object.
Motion
action or process of a change in position.
mass
amount of matter
why we use velocity in biomechanics and not speed?
because we care about direction we quantify the acceleration.
