You were introduced to levers in grade 7. Let’s go down memory lane and see what we remember about levers.
Watch video on youtube.com/watch?v=OdM2jWg2uEE and comment on the following.
- What do you understand by the term “lever”?
- Identify 3 different classes of levers.
- What are the differences between the 3 classes.
- Draw a simple lever and label 3 important parts.
- Identify in which class the following levers fall. Explain why you have classified it as such. (i) wheelbarrow (ii) scissors (iii) shovel (iv) stapler (v) car jack (vi) nutcracker (vii) crowbar (viii) hedge trimming sheers (ix) jaws of life.
1 . Lever : a rigid bar resting on a pivot ,used to move a heavy or firmly fixed load with one end when pressure is applied to the other .
2. First class ,second class ,third classs
3. The diffrence between the three classes depends on where the force is, where the fulcrum is and where the load is .
4:
5. I) second class levers the load is between the effort (force) and fulcrum.
II)first class lever the fulcrum is located between the load and the force.
III) third class lever ,the effort force lies between the resistance force and the fulcrum.
Iv) second lever is when the load is between the fulcrum and the effort .
V) third class lever between load and fulcrum
Vi) second class lever the fulcrum in the nutcracker is at one end ,where the two metal rods of the device are hinged together . The effort force is applied at the opposite ends of the rods ,and the resistance force,the nut to be cracked open ,lies in the middle
Vii)first class lever the fulcrum is placed between the effort and load to resemble a seesaw.
Viii) second class
Ix) first class
Great job Brendon for attempting this exercise. For question 3 it would be great if you explained the differences by means of examples ro clearly show the positions of the fulcrum, load and force for each example
1.I understand that it is a simple machine that has a beam or a rigid rod pivoted at a
hinge that is fixed or a fulcrum.
2.The 3 different types are the first;second and third class.
3.The difference between the three classes is that it depends on where the force
is,where the fulcrum and load are located.
Like for example~Class 1=has the fulcrum between the effort and the load.
Class 2=has the load in between the effort and the fulcrum.
Class 3=has the effort between the load and the fulcrum.
4.PHOTO WILL BE SENT.
5a)Wheelbarrow~Is a second class lever why because the dirt in the wheelbarrow is the
load,the fulcrum is the wheel and the force is at the end of the handles
where it’s lifted then pushed.
b)Scissors~Is a first class lever because it’s handles apply the force or the effort the
screw connecting the two sides forms the fulcrum and the force
transferred to the blade allows it to cut.
c)Shovel~Is a third class lever because the hand closest to the end acts as the fulcrum;
the second hand provides effort and the shovel end lifts and moves back.
d)Stapler~Is a third class lever because the load is situated between the fulcrum, or
pivoting point and the the point where effort pr force is applied.
e)Car jack~first class lever because the fulcrum lies between the force arm and the
lever arm.
f)Nutcracker~Is a second class lever because the fulcrum in the nutcracker is at one
end where the two metal rods and the resistance force for the nut to be
broken open.
g)Crowbar~Is a first class lever because the fulcrum is placed between the effort and
the load to resembles seesaw.
h)Hedge trimming sheers~Is a first class lever because the handles apply force or the
effort.
i)Jaws of life~Is a first class lever because the fulcrum is somewhere between the
effort and load.