Soc 20 - Levers

Question 1

What is a lever?

Answer 1

The term ‘lever’ refers to a system of muscles and bones working together to bring about movement.

Question 2

What are the four components of a lever?

Answer 2

.A Fulcrum (or pivot)
. A Load
. An Effort
. A Lever Arm

Question 3

What is a fulcrum (or pivot) ?

Answer 3

The point around which the lever rotates (joints)

Question 4

What is a load?

Answer 4

The force that is applied by the lever system. The load is the object you want to move, a dumb bell with your arm.

Question 5

What is an effort?

Answer 5

A force that is applied by the user of the lever system. The effort is applied by your muscles.

Question 6

What is a lever arm?

Answer 6

A rigid bar such as a bone.

Question 7

What is ‘FLE’?

Answer 7

. First class lever - Fulcrum sits in the middle 
. Second class lever - Load is in the middle
. Third class lever - Effort is in the middle

Question 8

What is the structure of a first class lever?

Answer 8

The fulcrum sits in the middle, between the load and the effort.

Question 9

What is an example of a first class lever in the body?

Answer 9

. In the body there are not many first class levers so few exercises use them 
. The main example of one of these exercises is a tricep dip. The elbow is the fulcrum which sits between the load (weight held in hand) and the effort applied by the tricep.

Question 10

What is the structure of a second class lever?

Answer 10

The load sits in the middle between the effort and fulcrum.

Question 11

What is an example of a second class lever in the body?

Answer 11

.Second class levers are also quite rare as they are less common in the body
. One example is a calf raise. The body weight (load) sits between the toes and the ball of feet (fulcrum) and the gastrocnemius muscles apply the effort by pulling the heel.

Question 12

What is the structure of a third class lever?

Answer 12

The effort is applied between the fulcrum and the load.

Question 13

What is an example of a third class lever in the body?

Answer 13

.Most of the levers in the body are third class levers. This is because the effort is applied between the fulcrum and load.
. One example is a bicep curl. The effort is applied by the biceps muscle, which is between the fulcrum at the elbow joint and the weight in your hands.

Question 14

What is a mechanical advantage?

Answer 14

This is when the output of the lever is greater than the impact - that is, when the load is greater than the effort, so you are getting more out than you are putting in. To calculate this you simply divide the input by the output.

Question 15

What levers work at a mechanical advantage?

Answer 15

First and second class levers.

Question 16

What is a mechanical disadvantage?

Answer 16

The opposite of mechanical advantage. This happens when the effort and the load are both the same aide of the fulcrum but the effort sits closer to the fulcrum than the load does. In this case, the input of the lever is greater than the output- the force you apply is greater than the loaf so you are putting in more than you are getting out.

Question 17

What levers work at a mechanical disadvantage?

Answer 17

Third class levers.