kinematic concepts

• The three types of motion are linear motion, angular motion and general motion.
• Linear motion is motion in a straight line.
• Angular motion is when a body moves along a circular path. Occurs around an axis.
• General motion is a combination of linear and angular motion
• Distance is the path travelled from start to finish, regardless of direction
• A sporting example of distance and displacement is a netball player dodging and weaving to get in front may have a distance of 20 meters but only a displacement of 5 meters.
• Displacement is defined as the change of position- how far it is from the initial position to the final position.
• Speed measures the distance by the time taken.

  Speed= distance/time
• Velocitiy measures the displacement an object experiences over time.

  Velocity= displacement/time
• Acceleration refers to the rate of velocity change experienced by an object over time.

  Acceleration= change in velocity/change in time
• When acceleration is 0, that doesn't mean that the object has stopped moving, but it is at a constant velocity.
• Angular Motion is caused by an eccentric force, which is a force that doesn’t act through an object's centre of gravity. This force causes objects to rotate and move forward. This effect is known as Torque.
• Torque is the force applied at a distance from the axis causing a turning effect.
• Angular distance is the total of all angular changes within a movement.

  Eg. Gymnast rotates around a bar 3.5 times and have a displacement of 540 degrees.
• Angular displacement is the angular difference between the starting and finishing points. Always the smaller angle.

  Eg. Gymnast rotates around the bar 3.5 times and has a displacement of 180 degrees.
• Angular speed is the angular distance covered divided by the time.

  Angular speed = angular distance / time
• Angular velocity is the rate of change in the angular displacement over time.

  Angular velocity = angular displacement / time
• Angular acceleration is the rate of change of angular velocity.
• As soon as an object is released into the air, it becomes a projectile and is under the influence of gravity and air resistance. This is projectile motion.
• The three influences on projectile motion are angle of release, speed of release and height of release.
• Angle of release is the angle (with respect to the horizontal ground) an object is projected into the air.
• Optimum angle of release is 45 degrees but some skills need higher (basketball free throw) or lower (javelin) depending on where the target is.
• The speed at which an object is thrown, kicked or propelled into the air is referred to as the speed of release. The greater the speed of release, the greater the distance the object will travel.
• The higher the height of release the further a projectile will travel.