5. Torque

Question 1

What is a Torque?

Answer 1

• A torque is a force that has a tendency, to rotate an object about an axis (might rotate an object
• Other names for a torque include; rotational force, moment of force, or moment (moment = dealing with rotation)
• A torque can be thought of as a twist to an object

Question 2

What three factors influence wether or not an object will rotate?

Answer 2

Question 3

Formula and Units

Answer 3

Torque (T) = Force x Moment arm
Units: Nm

Question 4

What is the torque that the force will generate about the axis of rotation?

Answer 4

T = F|d
T = (75N)(2.2m)
T = 165 Nm

Question 5

What is the torque that the force will generate about the axis of rotation?

Answer 5

T = (55sin60)(3.8)
T = (47.6)(3.8)

T = 181 Nm

Question 6

What is a Lever?

Answer 6

A relatively rigid object that may be made to rotate about an axis by the application of a force

Levers MAGNIFY the effect of a muscle

Question 7

What are the 3 Kinds of Levers?

Answer 7

There are three kinds of levers: first class, second class, and third class

Classified by the relative positions of the forces to the axis of rotation

Question 8

What are the 4 Things all levers consist of?

Answer 8

○ The rigid body: the system being moved

○ The fulcrum: the axis of rotation or pivot point

○ The effort: the input force or the applied force

○ The resistance: the output force

Question 9

What is the The effectiveness of a lever determined by?

Answer 9

The effectiveness of the lever is determined by the mechanical advantage

• The ratio of the output force to the input force
• Measured by the distances between the forces to the axis of rotation

Question 10

Mechanical Advantage

How can a force balance a larger resistance in this case?

Answer 10

A force can balance a larger resistance when the force arm is longer than the resistance arm

As mechanical advantage increases the lever is built for strength, but sacrifices speed

Question 11

How can a force move a resistance through a large ROM in this case?

Answer 11

A force can move a resistance through a large range of motion when the force arm is shorter than the resistance arm

As mechanical advantage decreases the lever amplifies speed and range of motion, but sacrifices strength

Question 12

What is a First-Class Lever?

Answer 12

Mechanical advantage maybe greater or less than 1

Examples? anatomical and practical

Question 13

What is a Second-Class Lever?

Answer 13

Mechanical advantage is always greater than 1

Examples? anatomical and practical

Question 14

What is a Third-Class Lever?

Answer 14

Mechanical advantage is always less than 1

Examples? anatomical and practical