11.2 Angular Motion

Question 1

What is angular motion?

Answer 1

• Refers to rotation and involves movement around a fixed point or axis

Question 2

When does angular motion occur?

Answer 2

• Occurs when a force is applied outside the centre of mass

Question 3

What is newtons 1st law?

Answer 3

• Resistance an object has to change in its state of motion
• An object will stay in place till a force is applied to move it

e.g. at the start of a floor routine a gymnast remains still until a force is applied in motion

Question 4

What is inertia?

Answer 4

• The bodies resistance to change in motion & is related to mass
• If you want to get an object with a large mass moving you have to apply more force in comparason to a tiny object

Question 5

What is newtons 2nd law?

Answer 5

• The size and direction of the force applied, determines the size and direction of the acceleration given to the object

e.g. to provide acceleration at the start of a race an athlete has to apply a large force internally through the gluteal, gastronemius & quadricpets to drive forward

Question 6

How do you calculate force?

Answer 6

Force= Mass X Acceleration

Question 7

What is Newtons 3rd Law?

Answer 7

• For every action there is an equal and opposite force
• Law describes what happens when two bodies (or objects) exert force on one another
• Action & reaction are equal & opposite & always occur in pairs

A&R force e.g swimmer pushes water in backwards direction
Water will then exert force on swimmer

Question 8

What is the ground reaction force?

Answer 8

• GRF= The equal and opposite force exerted on a performer who applied a muscular force on the ground
• This force is exerted on the ground by the body contact with it

Question 9

What is the formula for angular velocity?

Answer 9

Angular displacement/ Time taken

Question 10

What is the formula for angular acceleration?

Answer 10

Change in angular velocity/ Time taken

Question 11

What is your centre of mass?

Answer 11

• The point of balance
• Centre of mass is always moving depending on your movements

Question 12

What is the line of gravity?

Answer 12

• The line extending vertically downwards from the centre of mass

Question 13

Why is stability so important?

Answer 13

• A stable body position will enable an athlete to resist motion
• You cannot perform to your best if you are unbalanced

Question 14

What is the stability of an athlete affected by?

Answer 14

• The height of the centre of mass- lowering COM will increase stability
• The position of the athletes line of gravity- should be central over base support to increase stability
• The size of the athletes area of support- larger base support becomes- more stability increases
• Mass- Often the greater the mass the more stability there is because of increased inertia

Question 15

What factors affect the centre of mass?

Answer 15

• The mass of the body or object
• The size of the base of support- The lower the more stable - but if your mass moves too near base of support you will over balance
• The number of points in contact with the surface
• The closer the line of gravity is to the base of support- the more stable the body