P1 23. Levers

Question 1

what’s a lever

Answer 1

a rigid structure such as a bone that rotates around an axis

Question 2

what is a fulcrum (pivot)

Answer 2

the point around which the lever rotates (your joint)

Question 3

what is a load

Answer 3

the force applied by the lever system (the thing you want to move such as a weight, an arm or a leg)

Question 4

what is an effort

Answer 4

the force applied by the user of the lever system (effort supplied by your muscles)

Question 5

what are the three types of lever

Answer 5

first class
second class
third class

Question 6

what is a first class lever

Answer 6

when the fulcrum is in the middle
load, fulcrum, effort
when an athlete throws a javelin
elbow is fulcrum
effort is biceps and triceps (contracted to keep arm straight)
javelin is load

Question 7

what is a second class lever

Answer 7

load in the middle
fulcrum, load, effort
a calf raise
body weight is the LOAD sitting between the balls of the foot (FULCRUM) and the calf muscle applies EFFORT to life the heel off the floor

wheelbarrow raise position too

Question 8

what is a third class lever

Answer 8

effort in the middle
load, effort, fulcrum
occur when the effort is applied between the fulcrum and the load
a bicep curl
fulcrum is elbow
load is weight
effort is bicep pulling up

Question 9

how do you remember the different lever’s positioning

Answer 9

123FLE
F1L2E3

Question 10

what are 2 benefits of levers

Answer 10

large loads can be moved with a relatively small amount of effort
the distance the load can be moved or the speed with which it can be moved can be increased without an increase in effort

Question 11

what is a mechanical advantage

Answer 11

a large load can be moved with a relatively small effort

Question 12

what is a mechanical disadvantage

Answer 12

third class levers cannot lift as heavy load with the same amount of effort, due to the position of the effort and load from the fulcrum

Question 13

what is the effort arm

Answer 13

the distance between the fulcrum and the effort

Question 14

what is the load arm

Answer 14

the distance between the load and the fulcrum

Question 15

mechanical advantage

Answer 15

levers can move large loads with a relatively small amount of effort
have a high force to effort ratio
second class levers always have mechanical advantage
long jump take off
foot is in contact with the ground, effort is longer than load
the force produced is relatively small so full weight can be driven off the ground

Question 16

mechanical disadvantage

Answer 16

low load force to effort ratio
third class levers always have mechanical disadvantage
when bowling in cricket the arm is fully extended to generate the most speed
longer load arm, greater the speed

Question 17

what is the hip

Answer 17

third class
can’t produce the same load force to effort ratio as a second class lever
third class levers can take a small movement near the fulcrum and make a large movement where the load is

Question 18

what is it where the load arm is longer than the effort arm

Answer 18

mechanical disadvantage
third class
bicep curl

Question 19

what is it where the effort arm is longer than the load arm

Answer 19

mechanical advantage
first/second class
calf raise

Question 20

what happens if the fulcrum is closer to the load in a first class lever

Answer 20

relatively low effort will result in large more powerful movements at the load end, mechanical advantage

Question 21

what happens if the fulcrum is closer to the effort in a first class lever

Answer 21

lever will operate at mechanical disadvantage but will produce a large range of movement at the end of the lever and greater speed as a result

Question 22

why is a second class lever always a mechanical advantage

Answer 22

when a levers effort arm is longer than the load arm
move a large load will small effort
high load to force ratio

Question 23

why is a third class lever always a mechanical disadvantage

Answer 23

load arm is longer than the effort arm
low force to effort ratio
increase distance covered and speed
large range of movement with low effort
small movement near fulcrum and make large load actions which leads to large movement range and high speed
a rounders bat hit