LECTURE #12 - torques and moments of force

Question 1

what are torques ?

Answer 1

• the turning effect produce by a force
• anything that makes the object spin (the course)

Question 2

what are torques directly proportional to ?

Answer 2

the magnitude of force as well as the distance between the line of action of the force and the axis of rotation

Question 3

what is formula for torque ?

Answer 3

distance from pivot (in meters) x force (in newtons)

Question 4

Torque : motion fo a stained system has :

Answer 4

• has an acid of rotation
• one side is foxed in space (joints, fixed points, they don’t move)

Question 5

where is force applied with torque ?

Answer 5

force is applied away from the axis

Question 6

where is the line of action not with torque ?

Answer 6

line of action is not through the axis

Question 7

describe the four points of force in torque :

Answer 7

• magnitude
• point of application
• direction
• line of action

Question 8

how many factors of force is there in regards to torque ?

Answer 8

4

Question 9

describe the moment arm :

Answer 9

perpendicular distance between line of action of force and axis of rotation

Question 10

with elbow extension is angle getting smaller or bigger ?

Answer 10

bigger

Question 11

what is the axis of rotation also caused ?

Answer 11

the axis of rotation

Question 12

how do you calculate torque ?

Answer 12

Force x moment arm

Question 13

when the direction of a torque is counter clock wise, is it positive or negative ?

Answer 13

CCW = +

Question 14

when the direction of a torque is clock wise, is it positive or negative ?

Answer 14

CW = -

Question 15

what is one of the first steps in calculating torque ?

Answer 15

find perpendicular distance of moment arm then find x (or y depending on situation)

Question 16

what does rotary mean ?

Answer 16

• involves rotational force
• refers to the force applied to rotate an object around its axis
• involves twisting or turning motion

Question 17

what does non-rotary mean ?

Answer 17

• involves force applied without rotation
• include scenarios where force is exerted in a linear or fixed direction, such as pressing or tightening without any rotational movement

Question 18

what are the two “arms” in torque ?

Answer 18

lever and moment arm

Question 19

define lever arm :

Answer 19

• shorts distance between the axis of rotation and line of action of the force
• perpendicular to force’s line of action and axis of rotation

Question 20

define lever arm :

Answer 20

• distance between the point of force application (perpendicular component) and the axis of rotation * if you were to put line where is the 90 degree angle ??*

Question 21

where is the 90 degrees in the moment arm ?

Answer 21

• between the axis of rotation to the arm/distance
• insertion point must be distal for circle to occur

Question 22

where is the 90 degrees in the lever arm ?

Answer 22

• distance from point of application of the force

Question 23

in the moment arm what are we looking for ?

Answer 23

distance

Question 24

in the lever arm what are we looking for ?

Answer 24

perpendicular force

Question 25

in the wrench example, would we rather the shorter or the longer wrench ?

Answer 25

the longer (the extra length provides extra strength and more torque)

Question 26

what does ΣT stand for ?

Answer 26

some of all torque

Question 27

what should static equilibrium = in regards to distribution of torques ?

Answer 27

zero

Question 28

where do we see torque in humans ?

Answer 28

• muscles attach at some distance away from joint centre of rotation
• all muscle produce torque about the joints they cross

Question 29

what are the two muscle contributions (of internal moment) for joint moment :

Answer 29

• muscle force (tension)
• muscle lever arm

Question 30

what is concentric muscle action :

Answer 30

muscle interval moment and motion same direction (muscle force is bigger than external load & shortening when acting)