Lecture 13 - Ground Reaction Force (AI generated) Flashcards
What is friction and its role in motion?
Friction is the force developed between two surfaces that prevents slipping, allowing for acceleration of the body due to a force exerted by the ground on the foot.
It acts opposite to the direction of motion.
What is the formula for calculating friction?
The friction force is calculated as the product of the coefficient of friction (µ) and the normal force (F = µ * normal force).
What is the difference between static and kinetic friction?
Static friction exists between two surfaces not moving relative to each other and is proportional to the applied force.
Kinetic (dynamic) friction occurs during motion, is constant, and is less than the maximum static friction.
What factors determine the magnitude of friction?
The magnitude depends on the:
1.applied force
2.motion state
3.coefficient of friction (type of surfaces)
4.magnitude of the normal force.
What is the coefficient of friction?
A unitless number indicating the ease of sliding between two surfaces
different for static (µs) and kinetic (µk) conditions,
based on the relative roughness and hardness of the surfaces.
What is the normal force and its role in friction?
The normal force is the perpendicular force exerted by a surface, influencing friction. Reducing the normal force decreases the friction force.
What is rolling resistance?
Resistance to rolling, primarily due to deformation of the wheel and ground, not solely friction, with a smaller magnitude than friction between flat surfaces.
How do pulling and pushing affect friction?
Pulling reduces friction by decreasing the normal force, while pushing increases it due to the lack of a vertical force component, and increases further if a downward force is applied.
How does a fluid layer between surfaces affect friction?
A fluid layer reduces friction, with its magnitude influenced by the fluid’s nature, temperature, and the velocity between surfaces.
What are ground reaction forces and their components?
Forces exerted by the ground in response to forces we apply. Consists of a normal (push) force and a friction force, crucial for acceleration and preventing slipping.
