ধাক্কা: সংশোধিত সংস্করণের মধ্যে পার্থক্য
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৩ নং লাইন:
[[File:Engine.f15.arp.750pix.jpg|thumb|একটি [[Pratt & Whitney F100|প্র্যাট এবং হুইটনি এফ ১০০]] জেট ইঞ্জিন পরীক্ষা করা হচ্ছে। এই ইঞ্জিনটি গ্যাসের জেট তৈরি করে ধাক্কা সৃষ্টি করতে পারে। এর উদ্দেশ্য হ'ল তা দিয়ে জেট বিমান চালানো।]]
'''ধাক্কা''' হ'ল [[Newton's third law|নিউটনের তৃতীয় সূত্র]] দ্বারা পরিমাণগতভাবে বর্ণিত একটি [[reaction (physics)|প্রতিক্রিয়া]] [[force (physics)| বল]]। যখন কোনও সিস্টেম কোনও [[mass|ভর]] এর উপর কোনও অভিমুখে [[acceleration|ত্বরণ]] সৃষ্টি করে তখন ঐ ত্বরণ সম্পন্ন ভর ঐ সিস্টেমের উপর সমান [[magnitude (vector)|মান]] সম্পন্ন বিপরীতমুখী বল সৃষ্টি করে।<ref>{{cite web|url=https://www.grc.nasa.gov/WWW/k-12/airplane/thrust1.html|title=What is Thrust?|website=www.grc.nasa.gov|accessdate=2 April 2020|archive-url=https://web.archive.org/web/20200214214218/https://www.grc.nasa.gov/WWW/K-12/airplane/thrust1.html|archive-date=
The force applied on a surface in a direction perpendicular or [[normal vector|normal]] to the surface is also called thrust. Force, and thus thrust, is measured using the [[International System of Units]] (SI) in [[newton (unit)|newton]]s (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 [[Metre per second squared|meter per second per second]]. In [[mechanical engineering]], force [[orthogonal]] to the main load (such as in parallel [[helical gear]]s) is referred to as [[thrust (statics)|thrust]].
৯ নং লাইন:
[[Image:aeroforces.svg|thumb|Forces on an [[aerofoil]] cross section]]
A [[fixed-wing aircraft]] generates forward thrust when air is pushed in the direction opposite to flight. This can be done in several ways including by the spinning blades of a [[Propeller (aircraft)|propeller]], or a rotating [[Mechanical fan|fan]] pushing air out from the back of a [[jet engine]], or by ejecting hot gases from a [[rocket engine]].<ref>{{cite web|url=https://www.grc.nasa.gov/WWW/k-12/airplane/newton3.html|title=Newton's Third Law of Motion|website=www.grc.nasa.gov|accessdate=2 April 2020|archive-url=https://web.archive.org/web/20200203022807/https://www.grc.nasa.gov/WWW/K-12/airplane/newton3.html|archive-date=
A [[motorboat]] generates thrust (or reverse thrust) when the propellers are turned to accelerate water backwards (or forwards). The resulting thrust pushes the boat in the opposite direction to the sum of the [[momentum]] change in the water flowing through the propeller.
১৯ নং লাইন:
For vertical launch of a rocket the initial thrust at [[wikt:liftoff|liftoff]] must be more than the weight.
Each of the three [[Space Shuttle]] [[Space Shuttle Main Engine|Main Engines]] could produce a thrust of 1.8 [[meganewton]], and each of the Space Shuttle's two [[Space Shuttle Solid Rocket Booster|Solid Rocket Boosters]] {{convert|14.7|MN|lbf|abbr=on|lk=on}}, together 29.4 MN.<ref>{{cite web|url=http://www.braeunig.us/space/specs/shuttle.htm|title=Space Launchers - Space Shuttle|website=www.braeunig.us|accessdate=16 February 2018|archive-url=https://web.archive.org/web/20180406061909/http://www.braeunig.us/space/specs/shuttle.htm|archive-date=
By contrast, the [[simplified Aid For EVA Rescue]] (SAFER) has 24 thrusters of {{convert|3.56|N|lbf|abbr=on}} each.{{citation needed|date=April 2014}}
৮৪ নং লাইন:
===Thrust axis===
The thrust axis for an airplane is the [[line of action]] of the total thrust at any instant. It depends on the location, number, and characteristics of the jet engines or propellers. It usually differs from the drag axis. If so, the distance between the thrust axis and the drag axis will cause a [[moment (physics)|moment]] that must be resisted by a change in the aerodynamic force on the horizontal stabiliser.<ref>Kermode, A.C. (1972) ''Mechanics of Flight'', Chapter 5, 8th edition. Pitman Publishing. {{ISBN|0273316230}}</ref> Notably, the [[Boeing 737 MAX]], with larger, lower-slung engines than previous 737 models, had a greater distance between the thrust axis and the drag axis, causing the nose to rise up in some flight regimes, necessitating a pitch-control system, [[Maneuvering Characteristics Augmentation System|MCAS]].<ref>{{Cite web|url=https://www.aljazeera.com/news/2019/03/control-system-scrutiny-ethiopian-airlines-crash-190311094532350.html|title=Control system under scrutiny after Ethiopian Airlines crash|website=Al Jazeera|access-date=7 April 2019|archive-url=https://web.archive.org/web/20190428062403/https://www.aljazeera.com/news/2019/03/control-system-scrutiny-ethiopian-airlines-crash-190311094532350.html|archive-date=28 April 2019|url-status=live}}</ref><ref>{{Cite web|url=https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/|title=What is the Boeing 737 Max Maneuvering Characteristics Augmentation System?|date=14 November 2018|website=The Air Current|language=en-US|access-date=7 April 2019|archive-url=https://web.archive.org/web/20190407184426/https://theaircurrent.com/aviation-safety/what-is-the-boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/|archive-date=
==See also==
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