Mechanics 1

• Dr. Katalina Kariko and Prof. Drew Weissman


  They started research on mRNA technology in the late 1990s

  
• Breakthrough discovery in 2005

  Obtained a stable mRNA particle encoding a specific protein that, when delivered to the body, triggers an immune response

  
• COVID-19 mRNA vaccines


  Contributed greatly to controlling the pandemic (Pfizer and Moderna mRNA vaccines)

  
• 2023 Nobel Prize in Physics


  Awarded for new tools to explore the world of electrons inside atoms and molecules

  
• Pierre Agostini, Ferenc Krausz i Anne L'Huillier

  • Demonstrated a way to create extremely short pulses of light that can measure the extremely fast processes by which electrons move or change energy

  
• In human perception, rapidly changing events overlap, for example, movies - still images displayed so fast that we perceive them as continuous movement
• Attosecond


  One trillionth of a second, or 0.000,000,000,000,000,001 = 10−18 seconds
• Attosecond physics gives us a chance to understand the mechanisms that govern electrons
• Classical mechanics


  Study of the movement of material bodies on a macroscopic scale at low speeds compared to the speed of light in a vacuum
• Relativistic mechanics


  Refers to bodies moving at high speeds, even close to the speed of light in a vacuum
• Quantum mechanics


  Study of the movement of material bodies on a microscopic scale (on a molecular, atomic, nuclear scale, etc.)
• Kinematics


  Study of the movement of bodies without taking into account the acting forces, body masses and conditions of movement
• Dynamics


  1. Movement and balance of material bodies under the influence of the forces acting on them

  2. Kinetics - study of motion excluding equilibrium states

  3. Statics - dealing with equilibrium states
• Mechanics


  Department in physics describing the movement and deformation of material bodies or their parts as a result of their mutual interactions and examining the state of their equilibrium
• Classical mechanics


  Branch of mechanics describing the movement of bodies (kinematics), the influence of interactions on the movement of bodies (dynamics) and the study of the balance of material bodies (statics)
• Classical mechanics is based on the laws of motion (laws of dynamics) formulated by Isaac Newton, which is why it is called "Newtonian mechanics"
• Classical mechanics correctly explains the behavior of most bodies in our environment
• Modern Physics


  Began near the end of the 19th century, includes phenomena that could not be explained by classical physics, includes theories of relativity and quantum mechanics
• Aristotle's natural motion and violent motion

  Natural motion - straight up or down motion, heavy things fall and light things rise

  Violent motion - imposed motion with external cause, result of forces that pushed or pulled
• Aristotle believed rest is the proper state, if there were no force, there would be no motion
• Galileo's break from Aristotle

  Galileo demolished the notion that a force is necessary to keep an object moving
• Friction


  Force acting between materials as they move past each other, only when friction is present is a force needed to keep an object moving
• Ball rolling down an inclined plane

  Picks up speed
• Ball rolling up an inclined plane

  Slows down
• Ball rolling on a level surface


  Has almost constant speed, if there is no friction, the ball would move forever
• Ball released to roll down one inclined plane

  Rolls up to the other to reach nearly the same height, the smoother the planes the closer the heights
• Angle of the second inclined plane


  If smaller, the ball would roll farther to reach the same height
• Angle of the second inclined plane reduced to zero


  Only friction would keep the ball from rolling forever
• Inertia


  Tendency of a moving body to keep moving, property of a body to resist change in its state of motion
• Galileo proved that the mass of an object does not affect the rate at which it falls to the earth
• Galileo's law of free fall states that in a homogeneous gravitational field in the absence of other forces, all bodies fall with equal acceleration
• Heavier objects experience a greater gravitational force than a lighter object, but a heavier object is also harder to accelerate because it has more mass, so the extra mass exactly balances the additional gravitation force
• When an object falls there are two forces acting on it: the force of gravity pulling it down and the force of air resistance pushing it up
• The only solution to this paradox is to assume that objects fall regardless of their mass
• According to Galileo's theory, if you drop a cannonball and a bird feather on the moon, they should fall simultaneously
• Air resistance


  The force pushing the object up when it falls
• Net force on a falling object

  The force of gravity minus the force of air resistance
• Terminal velocity


  1. As the speed of a falling object increases, air resistance increases

  2. The upward force of air resistance continues to increase until it is equal to the downward force of gravity

  3. At this point, the net force is 0 N, and the object stops accelerating
• Free fall


  An object is in free fall only if gravity is pulling it down and no other forces are acting on it
• Free fall can occur only where there is no air or air resistance, such as in space or in a vacuum</b>