Biomechanics Flashcards
Moment of force (torque) =
Force (N) x Perpendicular distance from fulcrum (M)
Weight (N) =
Mass x Gravity
Distance =
Measured in meters. The path a body takes as it moves from the starting to finishing position.
Displacement =
Measured in meters. Shortest route in a straight line between start and finish position
Speed (m/s) =
Distance covered (m) ÷ Time (s)
Velocity =
Displacement (m) ÷ Time (s)
Average acceleration (m/s2) =
Change in velocity ÷ Time (s)
Change in velocity =
Final velocity - initial velocity
Momentum (kgm/s) =
Mass (kg) x Velocity (m/s)
Equilibrium
For a body to be in equilibrium, the sum of the clockwise moments must be equal to the anticlockwise moments around the fulcrum.
Newtons first law of linear motion
Law of Inertia - “The resistance an object has to change its state of motion”
Newtons second law of linear motion
Law of Acceleration - “The rate of acceleration is proportional to the force causing it and the change that takes place in the direction which the force acts”
Simply: The magnitude and direction of the force determines the magnitude and direction of the acceleration.
Newtons third law of linear motion
Law of Action / Reaction - “To every action, there is an equal and opposite reaction”
Newtons first law of angular motion
Law of Inertia - “The resistance an object has to change its state of angular motion (torque)”
Newtons second law of angular motion
“The rate of angular acceleration is proportional to the eccentric force causing it and the change that takes place in the direction which the turning force (torque) acts.”
Simply: The magnitude and direction of the torque determines the magnitude and direction of the angular acceleration.
Newtons third law of angular motion
“To every eccentric action, there is an equal and opposite eccentric reaction.”
What is angular displacement?
This is the smallest change in angle between the starting and finishing point
What is angular displacement measured in?
Radians (rad)
1 radian = 57.3 degrees
What is angular velocity?
Refers to the rotational speed of an object and the axis about which the object is rotating
Angular velocity =
Angular displacement (rad) / time (s)
What is angular acceleration?
Angular acceleration is the rate of change of angular velocity
Angular acceleration =
Angular velocity (rad/s) / time (s)
Angular momentum =
Angular velocity (rad/s) x moment of inertia
Impulse =
Force x Time
