Essential academy tutorials

Electronics is a branch of physics and engineering that deals with the study and application of devices and systems that use the flow of electrons to perform various functions. This field encompasses the design, development, and application of electronic circuits, components, and systems for a wide range of applications. Key concepts in electronics include: 1. Electronic Circuits: These are systems composed of interconnected electronic components such as resistors, capacitors, inductors, diodes, transistors, and integrated circuits. These circuits are designed to perform specific functions such as amplification, signal processing, and control. 2. Semiconductors: Semiconductors are materials with electrical conductivity between that of a conductor and an insulator. They form the basis of electronic devices such as diodes, transistors, and integrated circuits. 3. Digital Electronics: This area focuses on digital signals and systems, including digital logic gates, binary arithmetic, digital storage devices (e.g., memory), and digital communication systems. 4. Analog Electronics: Analog electronics deals with continuous signals and systems, including amplifiers, filters, oscillators, and analog-to-digital and digital-to-analog converters. 5. Power Electronics: Power electronics involves the control and conversion of electrical power using electronic devices such as power semiconductors, converters, inverters, and motor drives. 6. Electronic Devices: These include a wide variety of components such as diodes, transistors, sensors, displays, and integrated circuits that form the building blocks of electronic systems. The study of electronics is fundamental to many modern technologies, including telecommunications, computing, consumer electronics, medical devices, automotive systems, and industrial control systems. It also plays a crucial role in the development of emerging fields such as Internet of Things (IoT), robotics, and renewable energy systems.

Soap and detergent are both cleaning agents, but they have different compositions and uses. Soap: - Soap is a natural product made from the reaction of fats or oils with a strong alkali (such as sodium hydroxide or potassium hydroxide) in a process called saponification. - It is biodegradable and eco-friendly. - Soap molecules have a hydrophilic (water-attracting) head and a hydrophobic (water-repelling) tail, allowing them to interact with both water and oil, making them effective for cleaning. - Soap is commonly used for personal hygiene, handwashing, bathing, and general cleaning. Detergent: - Detergents are synthetic cleaning agents made from petroleum-based ingredients, surfactants, and other chemicals. - They are designed to be effective in hard water and have stronger surfactant properties than soap. - Detergents are less likely to leave a residue on surfaces and are often used in laundry detergents, dishwashing liquids, and household cleaning products. - They may also contain additives such as enzymes, bleach, and fragrances to enhance their cleaning properties. In summary, while both soap and detergent are used for cleaning, soap is a natural product made from fats and oils, whereas detergents are synthetic products made from petroleum-based ingredients. Each has its own advantages and specific uses in different cleaning applications.

Projectile motion is a fundamental concept in physics that describes the motion of an object that is launched into the air and moves under the influence of gravity. This type of motion can be observed in a wide range of scenarios, such as the motion of a thrown ball, a launched rocket, or a projectile fired from a weapon. The key characteristics of projectile motion include: 1. Horizontal Motion: The object moves horizontally at a constant velocity, unaffected by gravity, assuming no air resistance. This means that the horizontal component of the object's velocity remains constant throughout its flight. 2. Vertical Motion: The object moves vertically under the influence of gravity. As the object ascends, its vertical velocity decreases until it reaches its peak height, after which it descends with an increasing vertical velocity due to the acceleration caused by gravity. Key Equations for Projectile Motion: - The horizontal and vertical components of motion are independent of each other. Therefore, the equations for projectile motion can be separated into horizontal and vertical components. Horizontal Motion: - The horizontal distance traveled by the projectile (range) can be calculated using the equation: R = v0 * t * cos(θ), where R is the range, v0 is the initial velocity, t is the time of flight, and θ is the launch angle. Vertical Motion: - The vertical displacement of the projectile can be described using the equation: y = v0 * t * sin(θ) - (1/2) * g * t^2, where y is the vertical displacement, v0 is the initial vertical velocity, θ is the launch angle, g is the acceleration due to gravity, and t is the time. - The time of flight for the projectile can be determined using: t = (2 * v0 * sin(θ)) / g. - The maximum height reached by the projectile can be found using: ymax = (v0^2 * sin^2(θ)) / (2 * g). Projectile motion is an important concept in physics and has practical applications in fields such as sports, engineering, and ballistics. Understanding the principles of projectile motion allows us to analyze and predict the behavior of objects in motion under the influence of gravity.

Kepler's laws of planetary motion and Newton's law of universal gravitation are fundamental principles in the field of astronomy and physics that describe the motion of celestial bodies, particularly planets and other objects in space. Kepler's Laws of Planetary Motion: 1. Kepler's First Law (Law of Ellipses): This law states that the orbit of a planet around the Sun is an ellipse with the Sun at one of the two foci of the ellipse. This means that planets do not move in perfect circles but rather in elliptical orbits. 2. Kepler's Second Law (Law of Equal Areas): This law states that a line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. In other words, a planet moves faster when it is closer to the Sun and slower when it is farther away. 3. Kepler's Third Law (Law of Harmonies): This law establishes a relationship between a planet's orbital period and its distance from the Sun. It states that the square of a planet's orbital period is directly proportional to the cube of its average distance from the Sun. Newton's Law of Universal Gravitation: Isaac Newton's law of universal gravitation describes the attractive force between two objects with mass. The law states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. Mathematically, this is expressed as F = G * (m1 * m2) / r^2, where F is the force of gravity, G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between their centers. Newton's law of universal gravitation provides a quantitative explanation for Kepler's laws of planetary motion and is a foundational concept in understanding the behavior of celestial bodies within our solar system and beyond.

🔰 Answers for 2009 EUEE ___ #1) None of the furniture we bought last week _ yet. ባለፈው ሳምንት የገዛነው የቤት ዕቃ ገና ወደ ቤት አልመጣም። የቤት ዕቃው የተገዛው ባለፈው ሳምንት ነው፡ ነገር ግን ከባለፈው ሳምንት ጀምሮ እስከአሁን ድረስ የቤት ዕቃው ወደ ቤት አልመጣም። ስለዚህ ድርጊቱ ማለትም የተገዛው የቤት ዕቃ ወደ ቤት አለመምጣቱ፡  ከአሁን በፊት ወይም past ላይ ጀምሮ እስከአሁን ድረስ አልተከናወነም። ስለዚህ፡ present perfect + yet ደግሞ የሚያገለግለው ፡ ድርጊቱ ከአሁን በፊት ወይም past ላይ ጀምሮ እስከአሁን ወይም present ላይ ድረስ ያልተከናወነን ድርጊት ለመግለፅ ነው። ሁለት ሀሳቦችን እንረዳ፡ ሀሳብ 1: ድርጊቱ ከአሁን በፊት ወይም past ላይ ያልተከናወነ። ሀሳብ 2: ይህ past ላይ ያልተከናወነው ድርጊት ፡ አሁንም ላይ ወይም present ላይ ያልተከናወነ። ስለዚህ በሌላ አባባል ድርጊቱ ከ past ጀምሮ እስከ present ድረስ ያልተከናወነ ማለት ነው። ስለዚህ ፡ ሀሳብ 1: ባለፈው ሳምንት የተገዛው የቤት ዕቃ፡ በተገዛበት ዕለት ማለትም ባለፈው ሳምንት ወደ ቤት አለመሔዱ። ሀሳብ 2: ባለፈው ሳምንት የተገዛው የቤት ዕቃ ፡ አሁንም ላይ ወይም present ላይ  ወደ ቤት አለመሔዱ። ስለዚህ ድርጊቱ ማለትም የተገዛው የቤት ዕቃ ከአሁን በፊት ጀምሮ ማለትም ከባለፈው ሳምንት ጀምሮ እስከአሁን ድረስ ፡ ከተገዛበት ቦታ ወደ ገዢዎቹ  ቤት አለመሔዱ ፡ present perfect + yet ተጠቅመን እንገልፀዋለን ማለት። ስለዚህ፡ choice B ና choice D መልስ አይሆኑም። A ወይም C ነው መልስ ሊሆኑ የሚችሉት። እዚጋ ማስተዋል ያለብን ነገር፡ የዚህ ዐ.ነገር ባለቤት ወይም subject furniture የሚለው ስም ነው። furniture ደግሞ uncountable noun ነው። ስለዚህ singular verb ን ነው የሚወስደው ማለት ነው። ስለዚህ choice C ማለትም have arrived የሚለው መልስ አይሆንም።  ስለዚህ፡ 🐯 Choice A is the correct answer. So, None of the furniture we bought last week has arrived yet.(ባለፈው ሳምንት የገዛነው የቤት ዕቃ ገና ወደቤት አልመጣም።) እዚጋ ማስተዋል ያለብን ነገር፡ ጥያቄውን በዚህ መልክ👇👇👇 ሊያወጡት ይችላሉ። The furniture we bought last week __ yet. A) has arrived B) hasn't arrived C) have arrived D) haven't arrived መልሱ B ይሆናል ማለት ነው። ምክንያቱም perfect tenses + yet ሁልጊዜ የሚያገለግለው negative sentence ና Question form ላይ ብቻ ነው። #2)Classes begin only after you ____ registration. Choice A & D መልስ መሆን አይችሉም፡ ምክንያቱም ጥያቄው የሚናገረው ስለ present situation ነው። Choice C መልስ መሆን አይችልም፡ ምክንያቱም After, Before, until, when, as soon as etc የመሳሰሉትን future tense ላይ መጠቀም አንችልም። ስለዚህ፡ choice B is the correct answer. ምክንያቱም ፡ ጥያቄው የሚናገረው ስለ present situation ነው። " ክላስ የሚጀመረው ምዝገባ ካጠናቀክ በሗላ ነው።" #3) Next week this time, I ____ all my examinations. Choice A መልስ መሆን አይችልም፡ ምክንያቱም finish የሚለው ግስ state verb ስለሆነ ፡ continuous tenses ላይ መጠቀም አንችልም። Choice B መልስ መሆን አይችልም፡ ምክንያቱም next week this time የሚለው future ን ወይም ወደፊት የሚከናወንን ድርጊት የሚያሳይ ነው ። present perfect( have finished) ደግሞ future ላይ ወይም ወደፊት የሚከናወንን ድርጊት አይገልፅም። ስለዚህ choice C ወይም choice D ነው መልስ ሊሆኑ የሚችሉት። የዚህ ጥያቄ ዋና ሀሳብ፡ " ቀጣይ ሳምንት በዚህ ሰአት ፡ ሁሉንም ፈተናዎቼን እጨርሳለሁ።" ስለዚህ፡ ቀጣይ ሳምንት በዚህ ሰአት ፈተናዎቼን ጨርሼ ፡ ወይ እረፍት ላይ ነኝ ወይም ደግሞ የሆነ ስራ እየሰራሁ ነው። ስለዚህ፡ ሀሳብ 1: የተገለፀው ጊዜ ማለትም ቀጣይ ሳምንት ከዚህ ሰአት በፊት። ሀሳብ 2: ቀጣይ ሳምንት ከዚህ ሰአት በፊት የሚከናወነው የወደፊት ድርጊት ማለትም ሁሉንም ፈተናዎቼን ተፈትኜ መጨረስ። ስለዚህ፡ ከተገለፀው ጊዜ በፊት የሚከናወንን የወደፊት ድርጊት ለመግለፅ፡ future perfect ን እንጠቀማለን። ስለዚህ፡ Choice D is the correct answer. ለበለጠ መረጃ ስለ future perfect post ያደረግነው አለ ፡ እሱን ወደሗላ ተመልሳችሁ ማየት ትችላላችሁ። #4) I am sure you _ a good time staying here with me this comming summer. Choice B & C መልስ መሆን አይችሉም፡ ምክንያቱም this comming summer( በዘንድሮው ወይም በሚመጣው ክረምት) የሚለው future ን ወይም ወደፊት የሚከናወንን ድርጊት ነው የሚገልፀው። Choice A or Choice D ነው መልስ ሊሆኑ የሚችሉት። ሀሳብ 1: ወደፊት ወይም future ላይ የሚከናወነው ድርጊት ፡ ማለትም በሚመጣው ክረምት ጥሩ ጊዜ ማሳለፍ ወይም መኖር ሀሳብ 2: ይኸ ወደፊት የሚከናወነው ድርጊት ማለትም በሚመጣው ክረምት ጥሩ ጊዜ ማሳለፍ ለሆነ ጊዜ ያክል continuously መከናወኑ። ሀሳብ 3: ለሆነ ጊዜ ያክል continuously ጥሩ ጊዜ ማሳለፍ ስንል ደግሞ ክረምት ስለሆነ ለ 2 ወይም ለ 3 ወር continuously ጥሩ ጊዜ መኖር። ስለዚህ፡ ይህ ወደፊት የሚከናወነው ድርጊት ማለትም በሚመጣው ክረምት ጥሩ ጊዜ ማሳለፍ ለሆነ ጊዜ ያክል ለ 2 ወይም ለ 3 ወር continuously የሚከናወን ስለሆነ በ future continuous ይገለፃል። ስለዚህ፡ Choice D is the correct answer. #5).Choice A is the correct answer. Because going to is used for intention. #6) choice B is the correct answer.because present perfect + never is used to talk about an action you have never done in your life time. #7) I was very sad to hear your mother __. "የናትህን ሞት ስሰማ በጣም ነበር ያዘንኩት።" ስለዚህ፡ ድርጊት 1: እናቱ መሞቷ፡ የመጀመሪያው ድርጊት ነው። ድርጊት 2: የእናቱን ሞት መስማት ሁለተኛው ድርጊት ነው። ስለዚህ የመጀመሪያው ድርጊት በ past perfect ሲገለፅ ሁለተኛው ድርጊት በ simple past ይገለፃል። ስለዚህ፡ Choice B is the correct answer. ለበለጠ መረጃ ስለ past perfect post ያደረግነውን ወደሗላ ተመልሳችሁ ማየት ትችላላችሁ፡ በቂ ማብራሪያ ታገኛላችሁ። #8) Choice C is the correct answer.

ማጥናት የምትፈልጉትን ርእሰ ንገሩልን እኛም እናቀርብላችኋለን ።አብሮነታችህ ከኛ አይለይ share like madreg ayiresa

Newton's laws of motion are a set of three fundamental principles that form the basis of classical mechanics and describe the behavior of objects in motion. They were formulated by Sir Isaac Newton in the 17th century and are still widely used in physics and engineering to understand and predict the motion of objects. 1. Newton's First Law (Law of Inertia): This law states that an object at rest will remain at rest, and an object in motion will continue to move at a constant velocity in a straight line unless acted upon by an external force. In other words, an object will maintain its state of motion unless a net external force is applied to it. 2. Newton's Second Law (Law of Acceleration): This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Mathematically, it can be expressed as F = ma, where F is the net force applied to an object, m is its mass, and a is the resulting acceleration. 3. Newton's Third Law (Law of Action and Reaction): This law states that for every action, there is an equal and opposite reaction. When one object exerts a force on a second object, the second object simultaneously exerts a force of equal magnitude but in the opposite direction on the first object. These laws provide a framework for understanding the behavior of objects under the influence of forces and are essential for analyzing and predicting the motion of objects in a wide range of physical scenarios.

1. Food prices have been … steadily for at least ten years. a) rising b) lifting c) raising 2. I’ll have to study hard, … I can pass the exam. a) so that b) such c) in order 3. You … to eat if you are not hungry. a) needn’t b) haven’t c) don’t have 4. We’ll dance and … we’ll have lunch. a) straight away b) so c) then 5. She has to go to Germany for the next … of the training. a) step b) stage c) point 6. When the meeting had finished, we went … the plan once again. a) up b) down c) over 7. I locked the animals in the cage to … them from getting away. a) avoid b) hinder c) prevent 8. You’re … your time trying to persuade her. a) wasting b) losing c) missing

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Answer. 1.a 2.a 3.c 4.c 5.b 6.c 7.c 8.a

●Some key postulates or features of the Bohr model. 1. Quantized Energy Levels: Electrons in the hydrogen atom can only occupy certain orbits or energy levels. These orbits are quantized, meaning electrons cannot exist in between these defined energy levels. 2. Fixed Orbits: Electrons revolve around the nucleus in circular orbits. Each orbit corresponds to a specific energy level. The orbits are stationary and do not emit radiation while the electron is in a stable orbit. 3. Angular Momentum Quantization: The angular momentum of an electron in a particular orbit is quantized, meaning it can only take on certain discrete values. 4.Radiation Emission: An electron can jump from a higher energy orbit to a lower energy orbit by emitting a photon (quantum of light) with energy equal to the energy difference between the two orbits. This is known as emission. 5. Absorption of Radiation: Conversely, an electron can move to a higher energy orbit by absorbing a photon with energy equal to the difference in energy levels. This is known as absorption. 6.Electrostatic Attraction: The attraction between the positively charged nucleus and the negatively charged electron provides the centripetal force necessary to keep the electron in orbit. 7. Quantum Condition: The angular momentum of the electron is quantized according to the condition: \( mvr = \frac{n h}{2\pi} \), where \( m \) is the mass of the electron, \( v \) is its velocity, \( r \) is the radius of the orbit, \( n \) is a positive integer (quantum number), and \( h \) is Planck's constant. 8. Limitations: The Bohr model is limited to hydrogen-like atoms (those with a single electron, like He+, Li2+, etc.) and does not fully explain the behavior of more complex atoms.

1.A race car starts from rest on a circular track of radius 200 m. The car’s speed increases at a constant rate of 0.5 m/s 2. At the point where the magnitudes of the centripetal and tangential l accelerations are equal, the car has traveled a distance of A) 100 m C) 400 m B) 200 m D) 800 m 2.An object moves in a circular path of radius 0.5 m on a horizontal frictionless surface. The cord will break if its tension exceeds 16 N. What is the maximum kinetic energy of the object? A) 32 J                  C) 16 J B) 4 J                     D) 8 J 3. A 5 kg cart is moving horizontally at 6 m/s. In order to change its speed to 10 m/s, the net work done on the cart must be: A) 40 J                   C) 160 J B) 90 J                   D) 400 J 4. A 1 kg block is dropped from a height h above the top end of a vertical spring with k= 1200 N/m. If the block compresses the spring by 0.1 m and momentarily comes to rest, what is the height from which the block was dropped? A) 0.2 m                     C)0.4 m B) 0.3 m                     D) 0.5 m 5.  A wheel initially rotating at 2 rad/s accelerates at 3.5 rad/s 2 for 2 sec. Through what angle does the wheel rotate during 2 s? A) 11 rad                   C) 5 rad B) 8 rad                      D) 3 rad   6.A uniform meterstick is found to balance at the 50 cm mark when placed on a fulcrum. When a 50 gram mass is attached at the 10 cm mark, the fulcrum must be moved to the 40 cm mark for balance. What is the mass of the meter stick? A) 100 g                C) 150 g B) 200 g                D) 400 g =======Ans======= 1. A 2. B 3. C 4. D 5. A 6. C

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