Force Flashcards
What are the 2 types of force?
Internal
External
What is internal force?
Force generated by the sports performer with the contraction of skeletal muscles
What is an external force?
Forces that come from outside the body and act upon in
What are the 2 types of external force?
Vertical and horizontal
What are the 2 horizontal forces?
Friction
Air resistance
What are the 2 vertical forces?
Weight
Reaction
What is the definition of friction?
The force that opposes the motion of 2 solid surfaces in contact
What is the definition of weight?
The gravitational force that the earth exerts on a body
What is the definition of air resistance?
The force opposing the motion of a body travelling through the air
What is the definition of reaction?
The equal and opposite force exerted by a body in response to the action force placed upon it.
What is the definition of net force?
The sum of all forces acting on a body when all the individual forces have been considered
What happens if the net force is 0?
There is no change in motion, two or more forces are balanced so the body will remain at rest or uniform velocity.
What happens if there is a positive net force?
There is a change in motion, two or more forces are unbalanced so the body will accelerate, change direction or change shape.
What happens if there is a negative net force?
There is a change in motion, two or more forces are unbalanced so the body will decelerate, change direction or change shape.
Where does weight force act?
From the centre of mass downwards
How do you increase weight force?
The greater the mass, greater the weight force pulling the body downwards
When is weight force present?
Always
When is reaction force present?
When 2 bodies are in contact
When will a body accelerate upwards?
When the reaction force is larger than the weight force
What affects friction?
Roughness of ground surface
Roughness of contact surface
Temperature of surfaces in contact
Reaction force
How do you maximise friction?
Rough ground surface eg track
Rough contact surface eg spikes
High temperature eg F1 tires warm up lap
Bigger reaction eg more mass, more reaction, more friction
How do you minimise friction?
Smooth contact surface
Smooth ground surface
Smaller surface area between the 2 surfaces in contact
What is air resistance affected by?
Velocity Shape Frontal cross sectional area Smoothness of surface Density of air Mass of body
Explain how velocity affects air resistance
As velocity increases so does air resistance
Explain how shape affects air resistance
The more aerodynamic the less air resistance
A teardrop shape is the most streamlined
Explain how frontal cross sectional area affects air resistance
The smaller the frontal cross sectional area the less air resistance
Explain how smoothness of surface affects air resistance
The smoother the surface the less air resistance
Explain how density of air affects air resistance
The less dense the air the less air resistance
Explain how mass of body affects air resistance
The larger the mass the less air resistance will affect it as it has a higher inertia
What are some sports that minimise friction
Cycling, skating and curling
