الهندسة الميكانيكية 3 - موجات واصطدامات

General Information

• This document is a study guide for a Mechanical Engineering 3 course.
• The course is part of a training program offered by YAT Learning Solutions and the Productivity and Vocational Training Department (PVTD).
• The academic year is 2020/2021.
• Contact information and website for YAT Learning Solutions are included.

Unit 1: Thrust and Collisions

• Thrust is the product of force and the time it takes to apply the force. This is equivalent to the change in momentum.
• Thrust = ∆P = ∆t * F
• Thrust has the same direction as the force.
• Units of thrust: kg.m/s or N.s
• Types of Collisions:
  • Elastic collision: Momentum and kinetic energy are conserved.
  • Inelastic collision: Momentum is conserved, but kinetic energy is not.
  • Perfectly inelastic collision: Momentum is conserved, kinetic energy is lost, and the colliding objects stick together after the collision.

Unit 2: Oscillatory Motion

•  Oscillatory motion is a type of periodic motion where an object repeats its motion over a period of time. Examples include simple pendulums and the movement of a piston in an engine.
•  Periodic motion is repetitive motion that occurs regularly. Examples include the motion of planets and satellites, the piston in a machine, a simple pendulum, and electromagnetic waves. 
• Simple harmonic motion (SHM) is a special type of periodic motion where the restoring force is directly proportional to the displacement. 
• Displacement (x) is the distance of the oscillating object from its equilibrium position.
• Equilibrium position (X=0) is the point where the displacement of the oscillating object is zero and its velocity is maximum.
• Period (T) is the time taken for the oscillating object to complete one full oscillation.
• Frequency (f) is the number of complete oscillations per second and has the formula f = 1/T.
• Amplitude (A) is the maximum displacement of the oscillating object from its equilibrium position.
• Equations for SHM.
• Relationship between displacement, velocity, and acceleration of oscillating body vs time.

Unit 3: Transmission of Motion

• Transmission of motion involves the transfer of rotary motion from a driving shaft to a driven shaft. Methods include:
  • Belt and pulley systems:  -The speed of the driving pulley (n1) and the driven pulley (n2) are inversely proportional to their diameters (D1, D2): n1/n2 = D2/D1.
  • Gear systems: -Gear ratios (i) are determined by the number of teeth (Z1, Z2) on interacting gears in such a way that: i = n1 / n2 = Z2 / Z1.
  • Chain and sprocket systems: 
•  Speed relationships in multi-stage systems.

Unit 4: Power

• Power (P) is the rate at which work (W) is done.  P = W/t
• Units of Power:
  • Watts (W)
  • Horsepower (hp)   1 hp = 735 W
• Power in linear motion: P = F * v
• Mechanical power output:
  • Indicated power (IP): the theoretical maximum power produced by the engine.
  • Brake power (BP): the power output from the engine shaft.
  • Mechanical efficiency (η): the ratio of brake power to indicated power, η = (BP / IP ) * 100%.

Unit 5: Simple Levers

• Simple levers are simple machines that change the direction or magnitude of force.
• IMA (Ideal Mechanical Advantage) is the ratio of the distance the effort moves to the distance the load moves. IMA = XE/XW
• AMA (Actual Mechanical Advantage) is the ratio of load to effort: AMA = W/E
• Mechanical Advantage (η) is the efficiency and has the equation η = (AMA / IMA) *100%.
• Types of simple levers:
  • Simple wheel-axle.
  • Differential wheel-axle.
  • Simple winch.
  • Compound winch.
  • Simple press.
  • Simple screw jack.
  • Bevel gear jack.
  • Pulleys

Unit 6: Pulleys

• Pulleys are simple machines used for lifting loads over a distance.
• Types of pulley systems:
  • Fixed pulleys (single pulley)
  • Movable pulleys (single pulley).
  • Multiple pulley systems (block and tackle)
• Mechanical Advantage in pulley system

استعد لاختبار شامل في مجال الهندسة الميكانيكية 3. يغطي هذا الاختبار مواضيع الدفع، الاصطدامات، والحركة الاهتزازية. تأكد من فهمك لكيفية الحفاظ على الزخم والطاقة الحركية خلال أنواع مختلفة من الاصطدامات.