# final revision sheet for levers

```Complete the following sentences:
1---------------------is a fixed point around which the rigid bar
rotates
2-manual broom is considered a --------------class lever and is
used for ---------------------------- and ---------------------------3-nail clipper is a ------------------ class lever while the boat
paddles are considered ------------- class lever
4-law of lever states that ----------------------------------5-when the force arm is longer the resistance arm so it can be
-----------------class lever
6------------------------------- and-------------------------- are used to
avoid danger
7-when a lever increases force so this means it has ------------------------------------8--------------------------, ----------------------- and-------------------------are from the benefits of using levers
9-crowbar is a --------------------class lever and is used to ---------------------------------10 -------------------- and-----------------are first class levers while
------------------ and-----------------are third class levers
11-------------------is a rigid bar that rotates around affixed point
and affected by fulcrum and resistance
Write scientific term for each of the following:
1- A class of levers which always saves effort(--------------------)
2- A fixed point around which a rigid bar rotates (---------------)
3- Distance between fulcrum and resistance(---------------------)
4- A class of levers which never saves effort(---------------------)
5- Distance between force and fulcrum(---------------------)
6- Example of a lever where force arm is longer than
resistance arm (-------------------)
7- A lever used to increase speed(---------------------)
8- The scientist who invented the levers (-------------------------)
9- A class of levers to which the stapler belongs(----------------)
Give scientific explanation for the following:
1- Fish hook is third class lever
--------------------------------------------------------------------------2- Although crowbar is a first class lever it saves effort
----------------------------------------------------------------------------------------------------------------------------------------------------3- Second class levers always save effort
--------------------------------------------------------------------------4- Although third class levers never save effort they have
other benefits
----------------------------------------------------------------------------------------------------------------------------------------------------5- Water pump is considered a first class lever
---------------------------------------------------------------------------
Problems
1- In a first class lever the force affecting the lever was 20
newton and the distance between the force and fulcrum
was 30 cm if the resistance affecting this lever was 50 n
calculate the resistance arm and state whether it saves
effort or not
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------2- Ahmed was trying to fix his bike gear using his pincer he
wondered whether it will save his effort or not, help him
to find out the force required if the resistance is 50N and
the force arm is 30 cm and the resistance arm is 10 cm
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
3- Ali was fishing with a hook where the force arm is half the
resistance arm and the distance between the fish and the
fulcrum was 30 cm =30 cm. the force required to lift a fish
weighing 10 kg was 20 N calculate the force arm and write
the use of this lever
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------4- if the force arm in this lever
is 25 cm and the resistance arm is
5 cm
Will the lever be considered
Balanced? give reason
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------5- Habiba and hend sat on a seesaw. Habiba affected it by a
force of 50 newton, and the distance between her and the
fulcrum was 200 cm.hend affected the seesaw by a force
of 60 newton and the distance between hend and habiba
was 350 cm. find out if the seesaw is balanced or not and
why?
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------6- If the ratio between the length of the resistance arm and
the length of the force arm is 5:1 and the value of the
resistance force is 5 newton ,then the value of the effort
force will be ------------------------newton (1-25-5)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
7This farmer is using the Shadoof (very old tool) to get
water from the canal, if the value of resistance is 200 N at
each time of getting the water out, then:
a- find the effort required to lift the water
----------------------------------------------------------------------------------------------------------------------------------------------------------8- aly is using a 2 meters crowbar to move a rock weighing
400 newton . He placed the fulcrum 0.5 meters away from
the rock. How much effort is required to lift this rock?
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
```