Lecture 6 Torque

Question 1

Centric Forces cause

Answer 1

Linear (translational) motion only

Floating serve in Volleyball

Question 2

Eccentric (off-center) Forces (Torque) cause

Answer 2

ALWAYS cause rotational motion (sometimes linear motion too)

Topsin Serve in Volleyball

Question 3

Torques are also called

Answer 3

Moments of force

Question 4

Torque is……

Answer 4

a rotational effect of an eccentric force

Question 5

Net Torque

Answer 5

Torques acting around the same
axis may be summed.
Similar to “net force” concept

Static Equilibrium:
ΣT = 0
ΣF = 0

Dynamic Equilibrium:
ΣT = Iα
ΣF = ma

Question 6

Newton’s 1st Law:
Inertia

Answer 6

A body will stay at rest…

A body will continue to move with the same velocity unless….

A net force acts on the body

Question 7

Moment of Inertia (I)

Resistance to angular motion depends upon two things

Answer 7

1. Mass
2. Distribution of Mass

Question 8

Radius of Gyration:

and

Units:

Answer 8

Represents the object’s mass
distribution with respect to a given axis of
rotation

Units: kg x m^2

Question 9

Moments of Inertia: Whole Body

Answer 9

Notice how the moment of inertia is affected by:
* Different axes
* Body position