የምዕራፍ ማስታወሻዎችና የመልመጃ ጥያቄዎች

የ9ኛ ክፍል ፊዚክስ ምዕራፍ 5፦ ቀላል ማሽኖች

በዚህ ገጽ ያለው ሁሉ ለ9ኛ ክፍል የፊዚክስ መፅሐፍ ምዕራፍ 5 ነው፦ ምዕራፉ የሚሸፍነው፣ አጭር ማስታወሻዎቹ፣ የመልመጃ ጥያቄዎች ከመልሶቻቸው ጋር፣ እና ቪዲዮ ባለበት የትምህርቱ ቪዲዮ።

4
ካርዶች: 10
የምዕራፍ 5 የመልመጃ ጥያቄዎች: 82–113
የምዕራፍ 5 የመፅሐፍ ገጾች

ምዕራፍ 5 የሚሸፍነው

1.Simple Machines and their Purposes
2.Simple Machines at Home
3.Simple Machines at Work Place
4.Classification of Simple Machines
5.Mechanical Advantage, Velocity Ratio and Efficiency of Simple Ma
6.Designing Simple Machine

የምዕራፍ 5 አጭር ማስታወሻዎች

በ9ኛ ክፍል የፊዚክስ ገጽ ላይ በዚህ ምዕራፍ ሥር የተመዘገቡት ካርዶች። አንድ በአንድ ይክፈቱ።

የማሽን Efficiency: Mechanical Advantage እና Velocity Ratioቀመር

\eta = \frac{\text{MA}}{\text{VR}} = \frac{\text{Work output}}{\text{Work input}}

\eta = \frac{\text{MA}}{\text{VR}} = \frac{\text{Work output}}{\text{Work input}}

$\eta$: የማሽኑ Efficiency $\text{dimensionless}$
$\text{MA}$: Mechanical Advantage: የ Load እና Effort ንፅፅር $\text{dimensionless}$
$\text{VR}$: Velocity Ratio: Effort የተጓዘበት ርቀት ለ Load የተጓዘበት ርቀት $\text{dimensionless}$
$\text{Work output}$: ማሽኑ በ Load ላይ የሰራው ጠቃሚ Work $\text{J}$
$\text{Work input}$: በ Effort አማካኝነት ወደ ማሽኑ የገባ Work $\text{J}$

መቼ እንደሚጠቀሙበት

የማንኛውንም ቀላል ማሽን Efficiency ለማስላት ወይም Work output እና Work input ን ከ Mechanical Advantage እና Velocity Ratio ጋር ለማዛመድ ይጠቀሙበት።

ይጠንቀቁ

Mechanical Advantage፡ Velocity Ratio እና Efficiency ንፅፅሮች በመሆናቸው ምንም መለኪያ ዩኒት የላቸውም። በእውነተኛ ማሽኖች ውስጥ Efficiency ሁልጊዜ ከ 1 ወይም ከ 100 በመቶ በታች ነው።

ከGrade 9 Physics፣ ገጽ 82-113 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

ማሽኖች ጉልበትን ወይም Work ን አያባዙምየተለመደ ስህተት

መቼ እንደሚጠቀሙበት

ማሽኖች ጉልበት ይፈጥራሉ ወይም አጠቃላይ ስራን ይቀንሳሉ የሚሉ የፅንሰ ሀሳብ ጥያቄዎችን ለመመለስ ይጠቀሙበት።

ይጠንቀቁ

ማሽኖች በፍፁም Work ን ወይም ጉልበትን አያባዙም። አንድ ማሽን Force ን ወይም ፍጥነትን ሊያባዛ ይችላል፡ ነገር ግን ሁለቱንም በአንድ ጊዜ ማባዛት አይችልም። በፍጭት ምክንያት Work output ሁልጊዜ ከ Work input ያንሳል፡ ስለዚህ AMA ሁልጊዜ ከ IMA ያንሳል።

ከGrade 9 Physics፣ ገጽ 82-113 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

የሦስቱ የ Lever ክፍሎችየማጣቀሻ ሠንጠረዥ1st Class · 2nd Class · 3rd Class

ክፍል	መሃል ላይ የሚገኘው	የ IMA ባህሪ	ምሳሌዎች
1st Class	Fulcrum	$\text{IMA} > 1$ ፣ $\text{IMA} = 1$ ፣ ወይም $\text{IMA} < 1$	ሲሶ (seesaw)፣ መቀስ፣ ክራውባር (crowbar)
2nd Class	Load	$\text{IMA} > 1$	ዊልባሮ (wheelbarrow)፣ የለውዝ መሰበሪያ፣ የጠርሙስ መክፈቻ
3rd Class	Effort	$\text{IMA} < 1$	ትዊዘር (tweezers)፣ መጥረጊያ፣ የዓሣ ማጥመጃ ዘንግ፣ ጉጠት (tongs)

መቼ እንደሚጠቀሙበት

መሃል ላይ የሚገኘውን ነጥብ (Fulcrum: Load ወይም Effort) መሠረት በማድረግ የ Lever ክፍሎችን ለመለየት ይጠቀሙበት።

ይጠንቀቁ

የመሃል ክፍሉን ቅደም ተከተል ያስታውሱ፦ 1ኛ ክፍል Fulcrum መሃል ላይ ነው፤ 2ኛ ክፍል Load መሃል ላይ ነው፤ 3ኛ ክፍል Effort መሃል ላይ ነው።

ከGrade 9 Physics፣ ገጽ 82-113 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

የቀላል ማሽኖች Velocity Ratio እና IMAየማጣቀሻ ሠንጠረዥያዘነበለ ወለል (Inclined Plane) · Wedge · Screw · +2

ቀላል ማሽን	የ Velocity Ratio (VR) ቀመር	ምልክቶች
ያዘነበለ ወለል (Inclined Plane)	$\text{VR} = \frac{l}{h}$	$l = \text{የ slope ርዝመት},\; h = \text{ከፍታ (height)}$
Wedge	$\text{VR} = \frac{l}{t}$	$l = \text{የ penetration ርዝመት},\; t = \text{ውፍረት (thickness)}$
Screw	$\text{IMA} = \frac{2\pi r}{p} = \frac{\pi d}{p}$	$r = \text{radius},\; d = \text{diameter},\; p = \text{pitch}$
Wheel and Axle	$\text{VR} = \frac{R}{r}$	$R = \text{የ wheel radius},\; r = \text{የ axle radius}$
የ Pulley ሥርዓት (Pulley System)	$\text{VR} = N$	$N = \text{load የሚደግፉ የገመድ ዘንጎች ቁጥር}$

መቼ እንደሚጠቀሙበት

የማሽኑን አካላዊ ልኬቶች በመጠቀም የ Velocity Ratio ወይም Ideal Mechanical Advantage ን ለማስላት ይጠቀሙበት።

ይጠንቀቁ

በ Screw ጊዜ Pitch የሚባለው በክርክሮቹ መካከል ያለው ርቀት ነው። በ Wheel and Axle ጊዜ የ Effort ራዲየስ ለ Load ራዲየስ መካፈሉን ያረጋግጡ።

ከGrade 9 Physics፣ ገጽ 82-113 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

የምዕራፍ 5 የመልመጃ ጥያቄዎች

በዚህ ምዕራፍ ላይ የተጻፉ 10 የምርጫ ጥያቄዎች፣ እያንዳንዳቸው መልሱና ምክንያቱ አላቸው። መልሱን ከመክፈትዎ በፊት ይሞክሩ። ጥያቄዎቹ በእንግሊዝኛ ናቸው።

ጥያቄ 1

What is the main purpose of using a simple machine?

A.To create energy out of nothing
B.To make mechanical work easier
C.To reduce the amount of total work required to zero
D.To increase the mass of an object

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B To make mechanical work easier

ምክንያቱ

A simple machine is a device that helps us do mechanical work more easily. Simple machines do not create energy; they only transfer it.

ጥያቄ 2

Simple machines are classified into two main groups: inclined planes and levers. Which of the following belongs to the inclined plane group?

A.Pulley
B.Wheel and axle
C.Wedge
D.Crowbar

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ C Wedge

ምክንያቱ

The inclined plane group consists of the ramp (inclined plane), wedge, and screw. Pulleys and wheel and axles belong to the lever group.

ጥያቄ 3

What term is used for the force applied to a simple machine by an external body, such as a person?

A.Effort
B.Load
C.Friction
D.Work output

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ A Effort

ምክንያቱ

Effort is the force exerted on a machine by an external body like a human being, while load is the force exerted by the machine on the object being moved.

ጥያቄ 4

In a second-class lever, which part is located in the middle between the other two?

A.The fulcrum
B.The load
C.The effort
D.The axle

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B The load

ምክንያቱ

In a second-class lever (such as a wheelbarrow), the load is placed in the middle, between the fulcrum and the effort.

ጥያቄ 5

A person in Gojjam uses a claw hammer to pull out a nail. An effort of 20 N is applied to pull a load force of 100 N. What is the mechanical advantage (M.A) of the hammer?

A.0.2
B.5
C.80
D.120

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B 5

ምክንያቱ

Mechanical advantage is calculated as: M.A = Load / Effort. Here, M.A = 100 N / 20 N = 5.

ጥያቄ 6

An inclined plane in Addis Ababa is used to slide heavy goods into a warehouse. The slope has a length of 30 m and raises objects to a vertical height of 5 m. What is the velocity ratio (V.R) of this inclined plane?

A.0.17
B.6
C.25
D.150

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B 6

ምክንያቱ

For an inclined plane, V.R = length of inclined surface (l) / height of inclined plane (h). Thus, V.R = 30 m / 5 m = 6.

ጥያቄ 7

A simple machine provides a work output of 80 J when 400 J of work is supplied to it. What is the efficiency of this machine?

A.20%
B.50%
C.80%
D.320%

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ A 20%

ምክንያቱ

Efficiency is defined as: η = (work output / work input) × 100%. So, η = (80 J / 400 J) × 100% = 0.2 × 100% = 20%.

ጥያቄ 8

A lever has its effort located 40 cm from the fulcrum and its load located 10 cm from the fulcrum. What is the velocity ratio (V.R) of this lever?

A.0.25
B.4
C.30
D.50

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B 4

ምክንያቱ

For a lever, V.R = distance from effort to fulcrum (d_E) / distance from load to fulcrum (d_L). Here, V.R = 40 cm / 10 cm = 4.

ጥያቄ 9

A machine has a mechanical advantage (M.A) of 3 and a velocity ratio (V.R) of 6. What is the efficiency of this machine?

A.18%
B.20%
C.50%
D.200%

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ C 50%

ምክንያቱ

Efficiency expressed in terms of M.A and V.R is: η = M.A / V.R. Here, η = 3 / 6 = 0.5 = 50%.

ጥያቄ 10

A wheel and axle is used to lift a bucket of water from a deep well near Hawassa. The radius of the wheel is 30 cm and the radius of the axle is 5 cm. What is the velocity ratio (V.R) of this wheel and axle?