Levers - First & Second Class Levers

Question 1

Describe orientation of force, axis and resistance in first class lever

First class levers are unlikely to come up

Answer 1

Force - Axis - Resistance

Question 2

Describe orientation of axis, force and resistance in second class levers

Second class levers are unlikely to come up

Answer 2

Axis - Resistance - Force

Question 3

What characteristic do all Second class levers possess?

Answer 3

They are all force multipliers

Question 4

Describe relationship between force and resistance in second class levers

Answer 4

Less force required to move a resistance

Question 5

Which is always longer; resistance arm or force arm for second class levers?

Answer 5

Force Arm

Question 6

What is the range for mechanical advantage in second class levers

Answer 6

Greater than 1

Question 7

Describe some examples of second class levers

Answer 7

• Standing on tippy-toes
• All eccentric contractions (consider gravity as force)

Question 8

Describe a unique characteristic of first class levers for their mechanical advantage range

Answer 8

Can be greater than or less than 1 mechanical advantage

Can be manipulated to either increase speed or force

Question 9

Describe what determines whether mechanical advantage is greater than or less than 1 for first class levers

Answer 9

The distance between axix and eitehr resistance arm or force arm
* Axis closer to force arm is mechanical advantage less than 1
* Axis closer to resistance arm is mechanical advantage greater than 1

Question 10

Describe result of increasing force arm in first class lever

Answer 10

Force will increase

Question 11

Describe result of increasing resistance arm in second class lever

Answer 11

Speed will be increased

Question 12

Give a few examples of first class levers

Answer 12

• Nodding head
• See-saw