Principals of Force Flashcards
force
a push or a pulling action applied upon an object.
inertia
The resistance of an object to any change in its state of motion.
newtons 1st law of motion
‘an object in motion stays in motion at the same speed and in the same direction, and an object at rest stays at rest unless acted upon by an external force’
1st law example
A football will stay at rest on penalty spot until its acted on by an external force. Once kicked it will stay at the same speed towards the goal until another external force acts on it.
force equation
Force = mass(kg) x acceleration(a)
F = ma
acceleration
the rate at which an object changes speed.
Newtons 2nd law of motion
‘an object will accelerate when acted upon by an external force. The acceleration of the object is proportional to this force and is in the direction by which the force acts.
Newtons 3rd law of motion
‘for every action there exists and equal and opposite reaction’
Gravity
the force that attracts a body towards the centre of the earth
muscular force
a push or pull applied to an object, provided by muscular contraction
air resistance
the frictional force that air applies against a moving object
Rugby example:
Gravity will always pull the rugby ball towards the pitch
air resistance will affect the distance and accuracy achieved with a kick
if you don’t apply enough muscular force when passing the ball it might not reach your teammate
ground reaction force
the reaction to the force that the body exerts on the ground
acceleration phase in a sprinter
- athletes gone from a state of balanced forces to unbalanced forces, so accelerations occurred. Muscular force is greater than air resistance
- When pushing against blocks at start the ground reaction force from blocks result in explosive start.
Maximum speed in a sprinter
- muscular force reduces as fatigue sets in
- speed increases and muscular force reaches its optimum balance against air resistance, acceleration stops and maximum speeds reached
