Biomechanics

Question 1

Linear Motion

Answer 1

• Occurs when all body parts move the same distance and direction at the same time.
• Eg. Side-on shotput technique.
• Sometimes referred to as translation.

Question 2

Angular Motion

Answer 2

• Occurs when body parts rotate in the same direction around a fixed point.
• Point known as axis of rotation.
• Eg. Bicep Curl
• Eg. Gymnast swinging around bar.

Question 3

Acceleration

Answer 3

• The rate at which velocity changes with respect to time.

Question 4

General Motion

Answer 4

• The most common motion of humans.
• Combination of linear and angular motion.
• Eg. Long Jump

Question 5

Newton’s First Law of Motion

Answer 5

• All bodies will continue in a state of rest or uniform motion in a straight line unless acted on by some external force.

Question 6

Newton’s Second Law of Motion

Answer 6

• The acceleration of a body is proportional to the force acting on it and takes place in the direction the force acts.

Question 7

Newton’s Third Law of Motion

Answer 7

• For every action there is an equal and opposite reaction.

Question 8

Summation of Momentum

Answer 8

• Used to maximise speed of smaller limbs.
• Goes from largest to smallest body parts.
• All required joints must be used and timed so that the switch to the next joint at peak velocity.
• Joints must be used in order.

Question 9

Accuracy (Simultaneous)

Answer 9

• Not dependant on maximisation of force
• Focuses on getting the right distance and direction
• “Flatten the Arc”

Question 10

Balance

Answer 10

• Balance refers to the ability of a body to maintain stability or equilibrium when stationary or moving.

Question 11

Factors Affecting balance and stability

Answer 11

• Size of the base of support
• Position of the centre of gravity
• Line of gravity
• Mass of the body

Question 12

Size of the base of support

Answer 12

• Base of supported is bounded by the body parts in contact with a surface.
• The wider the base of support, the more stable the body is.

Question 13

Position of the Centre of Gravity

Answer 13

• The theoretical point through which all the weight of an object appears to act.
• The lower the centre of gravity, the better the stability.

Question 14

The Line of Gravity

Answer 14

• Closer the line of gravity is to directly over the centre of the base of support, the greater the stability.
• Line drawn from centre of gravity to be perpendicular with ground.

Question 15

Mass of the Body

Answer 15

• A person with larger mass is more stable (Inertia)

Question 16

Factors Affecting the Path of a Projectile

Answer 16

• Velocity at release
• The angle of projection
• The height of release
• Air resistance and spin

Question 17

Velocity at Release

Answer 17

• Increasing the velocity at release increases the height of the flight path, the length of time spent in the air and the distance travelled.

Question 18

Angle of Projection

Answer 18

• 45 degrees is ideal projection
• Less than 45 results in a flatter, but faster trajectory
• Higher than 45 results in a higher and slower trajectory.
• Demands of sport affect the angle of projection.

Question 19

Height of Release

Answer 19

• Shot from the ground, the best angle of projection for distance is 45 degrees.
• If the object is starting from above the landing area, the angle will be lower than 45.
• Below the landing area = higher than 45

Question 20

Air Resistance and Spin

Answer 20

• Increased air resistance will decrease air time and distance of projectile.
• The greater the surface area of an object, the more air resistance it picks up.
• Magnus Effect: when the spin on the ball causes the air to heat up around it and create a high pressure system on one side of the ball. Used to curve the ball.