Chapter 4 Biomechanical Principles Flashcards
What is biomechanics?
The study of human movement using mechanical principles to optimize performance and prevent injury.
What are the two main types of motion?
Linear motion (straight-line movement) and angular motion (movement around an axis).
Define general motion.
A combination of both linear and angular motion, such as running.
What is mass?
The quantity of matter in an object, typically measured in kilograms.
Define inertia.
The resistance of an object to changes in its state of motion.
What is force?
A push or pull that changes an object’s state of motion, calculated as Force = Mass × Acceleration (F = ma).
What are the two types of forces?
Internal forces (muscular contractions) and external forces (gravity, friction).
Define torque.
A rotational force applied at a distance from an axis, causing angular motion.
What is the difference between speed and velocity?
Speed is how fast something moves, while velocity includes direction.
Define acceleration.
The rate of change of velocity over time.
State Newton’s First Law of Motion (Law of Inertia).
An object will stay at rest or continue moving at a constant velocity unless acted upon by an external force.
Explain Newton’s Second Law of Motion.
The acceleration of an object is proportional to the force applied and inversely proportional to its mass (F = ma).
What does Newton’s Third Law of Motion state?
For every action, there is an equal and opposite reaction.
How does Newton’s First Law apply to a moving cyclist?
The cyclist will keep moving unless friction, air resistance, or braking stops them.
What happens to acceleration if mass increases but force stays the same?
Acceleration decreases.
Define momentum.
The product of an object’s mass and velocity (Momentum = Mass × Velocity).
What is the principle of conservation of momentum?
Momentum is conserved in a system unless acted upon by an external force.
Define impulse.
The change in momentum, calculated as Impulse = Force × Time.
How does increasing time of contact affect impulse in catching a ball?
It reduces the force experienced, making the catch easier.
Why is impulse important in sports like long jump?
A longer force application increases momentum, leading to greater distance.
What are the three classes of levers?
First-class (seesaw), second-class (wheelbarrow), and third-class (biceps curl).
Which class of lever is most common in the human body?
Third-class levers, where force is applied between the axis and resistance (e.g., a baseball bat swing).
Define mechanical advantage.
The ratio of force arm to resistance arm in a lever system.
How does a longer resistance arm affect speed?
It increases speed at the end of the lever, useful in sports like tennis.
What is the equation for torque?
Torque = Force × Moment Arm.
Define equilibrium.
A state where all forces and torques are balanced, preventing motion.
What factors affect stability in sports?
Base of support, center of gravity, and line of gravity.
How does lowering the center of gravity affect stability?
It increases stability, making it harder to be knocked over.
What is line of gravity, and why is it important?
An imaginary vertical line through an object’s center of mass; balance is better when it stays within the base of support.
How does widening the base of support affect balance?
It increases stability, helping athletes maintain control.
