Force Summation and levers

Question 1

what is force summation

Answer 1

the order of recruitment of muscle groups at their peak force production

Question 2

what is the order of the variables of all the lever classes

Answer 2

first-class - resistance, fulcrum, applied force
second-class - fulcrum, resistance, applied force
third-class - fulcrum, applied force, resistance

Question 3

what is the effort arm and resistance arm

Answer 3

effort - the distance between the fulcrum and the applied force
resistance - the distance between the fulcrum and the resistance

Question 4

which lever is a force multiplier and how does it multiply force

Answer 4

first and second-class levers
Force multipliers have a longer effort arm than the resistance arm, as a result the mechanical advantage of these levers is always greater than one

Question 5

which lever is a speed multiplier and how does it multiply speed

Answer 5

In third-class levers, speed multipliers have a resistance arm that is longer than the effort arm. As a result, the load has to travel a greater distance, which in turn multiplies its speed.

Question 6

advantages of third and second-class levers

Answer 6

second class:
Advantage: can move large loads with little effort
Disadvantage: can’t move loads as far as third-class levers; slow to work

third class:
Advantage: load moves further and faster creating speed and power
Disadvantage: short effort arm means muscles need to exert more effort than the mass of the load