Angular Kinetics

Question 1

Eccentric force

Answer 1

away from CoG

Question 2

Torque is defined as..

Answer 2

• as the turning effect of a force
• the tendency of a force to cause rotation
• the product of force and moment arm

Question 3

Angular Inertia

Answer 3

property of an object to resist change in its angular motion

Question 4

Influencing variables of Angular Inertia

Answer 4

mass
distribution of mass
(k is more important hence “k2”)

Question 5

Angular Momentum

Answer 5

product of the angular inertial property (moment of inertia ) and angular velocity

Question 6

three factors that affect angular momentum

Answer 6

mass
distribution of mass
angular velocity

Question 7

Conservation of Angular Momentum

Answer 7

total angular momentum remains of a given system remains constant in the absence of external torques

Question 8

Gravity does not affect angular momentum of a rotating body in the air why?

Answer 8

gravitational force acts through the centre of gravity, therefore no torque

Question 9

What are Levers

Answer 9

hinged, rigid structure (around a point), and the forces acting around that point

Question 10

Hinged point

Answer 10

=axis of rotation (fulcrum)

Question 11

Examples of a 1st class lever

Answer 11

• seesaw

- atlanto-occpital joint

Question 12

Examples of a 2nd class lever

Answer 12

• wheel barrow

- ankle on tip toes

Question 13

Examples of 3rd class lever

Answer 13

• fishing rod

- elbow

Question 14

Force arm and resistance arm

Answer 14

a lever of any class will balance when the product of the force arm (FA) and the force (F) is equal to the product of the resistance arm (RA) and the resistance (R)

Question 15

Mechanical Advantage in levers

Answer 15

MA=FA/RA 
3rd class levers have poor MA human body built for speed not strength

Question 16

What is Angular Acceleration?

Answer 16

• REVIEW: Newtons 2nd law: acceleration of a body is proportional to and takes place in the direction in which the force acts. Also inversely proportional t the boys mass.
• Angular Acceleration: change in angular momentum of an object is proportional to and in the direction of the net external torque exert on it. Inversely proportional to moment of Inertia.

Question 17

What is Angular action-reaction?

Answer 17

• REVIEW: Newtons 3rd law: for every force there is an equal and opposite force exerted by the second body on the first
• Angular action-reaction: for every torque exerted by one object on another, the other object exerts an equal torque back on the first object but in the opposite direction ex. muscle attachments