CH3, CH4 CH6

• force is defined as push or pull. measured in newtons (n) is mass x acceleration. can affect an object by changing its shape or moving the object
• types of force: friction occurs when two surfaces come in contact with eachother, it opposes the motion of the object and increasing or decreasing friction can be beneficial
• types of force: air and water resistence - an object moving through air/water/gas will experience drag force. it opposes the direction of the object which slows it down
• types of forces: gravitational force is the force of attraction between two bodies. on earth, gravitational force pulls you down
• types of forces: weight = mass x gravity, is the force that is exerted on the body by gravity
• inertia is the resistence to change. an object will continue to travel unless an external force is acted upon it. mass = more reluctant, to beat its reluctance must apply more force than inertia. eg. kicking a soccer ball thats coming at you away
• momentum = mass x velocity (m/s KG, without gravity) its the measure of the amount of motion an object has and its resistence to changing it. to generate more momentum, you transfer momentum from larger body parts like hips to your arm if your throwing to generate more power
• impulse = force x time, which is known as changing the momentum of the object. manipulating impulse can decrease risk of athlete injury. eg. wicket keeper catching ball and dragging arms back to increase time in contact with ball to lessen the force of the ball, making it easier to catch
• newton’s first law of motion 'a body will remain at rest on in uniform in a straight line unless acted upon by an external force'
• newton’s second law of motion ' a force applied to an object will produce a change in motion (acceleration) in the direction of the applied force that is directly proportional to the size of the force' - must go in direction that force is
• newtons 3rd law of motion 'for every action there is an equal and opposite reaction' eg. bouncing a bouncy ball comes straight back to you
• newton’s first law of angular motion “the angular momentum of a body remains constant unless acted upon by an external torque”
• newton’s second law of angular motion “a torque applied to an object will produce a change in angular motion in the direction of the applied torque that is directly proportional to the size of the torque and inversely proportional to the moment of inertia of the object”
• a torque is a force that tends to cause a rotation
• angular momentum is the amount of angular motion possessed on a body. eg how fast something is spinning
• angular momentum = moment of inertia and angular velocity
• moment of inertia = mass x radius^2
• moment of inertia is the rotational inertia of a body. eg. hammer throw
• summation of momentum

  a sequence of movements to maximise velocity.

  requires a stable base of support, use as many muscles as possible, use large muscle groups first then transfer velocity to small and then finish with a follow through.
• conservation of momentum

  when 2 bodies collide, combined momentum is conserved.

  eg. bowling as momentum of ballis greater than pins and momentum of ball gets transferred into pins but momentum stays the same.
• equilibrium is when there is no unbalanced forces or torques acting upon an object
• stability is the resistence to the disruption of equilibrium
• balance is the ability to control equilibrium
• to increase stability, you require a lower centre of gravity, wider or larger base of support, appropriate line of gravity and great body mass