AskDefine | Define thrust

Dictionary Definition

thrust

Noun

1 the force used in pushing; "the push of the water on the walls of the tank"; "the thrust of the jet engines" [syn: push]
2 a thrusting blow with a knife or other sharp pointed instrument; "one strong stab to the heart killed him" [syn: stab, knife thrust]
3 the act of applying force to propel something; "after reaching the desired velocity the drive is cut off" [syn: drive, driving force]
4 verbal criticism; "he enlivened his editorials with barbed thrusts at politicians"
5 a sharp hand gesture (resembling a blow); "he warned me with a jab with his finger"; "he made a thrusting motion with his fist" [syn: jab, jabbing, poke, poking, thrusting]

Verb

1 push forcefully; "He thrust his chin forward"
2 press or force; "Stuff money into an envelope"; "She thrust the letter into his hand" [syn: stuff, shove, squeeze]
3 make a thrusting forward movement [syn: lunge, hurl, hurtle]
4 impose or thrust urgently, importunately, or inexorably; "She forced her diet fads on him" [syn: force]
5 penetrate or cut through with a sharp instrument [syn: pierce]
6 geology: thrust (molten rock) into pre-existing rock
7 push upward; "The front of the trains that had collided head-on thrust up into the air" [syn: push up]
8 place or put with great energy; "She threw the blanket around the child"; "thrust the money in the hands of the beggar" [syn: throw]

User Contributed Dictionary

English

Pronunciation

  • /ˈθɹʌst/, /"TrVst/
    Rhymes: -ʌst

Etymology

From þrysta.

Noun

  1. An attack made by moving the sword parallel to its length and landing with the point.
    Pierre was a master swordsman, and could parry the thrusts of lesser men with barely a thought.
  2. A push, stab, or lunge forward (the act thereof.)
    The cutpurse tried to knock her satchel from her hands, but she avoided his thrust and yelled, "Thief!"
  3. The force generated by propulsion, as in a jet engine.
    Spacecraft are engineering marvels, designed to resist the thrust of liftoff, as well as the reverse pressure of the void.
  4. The primary effort; the goal.
    Ostensibly, the class was about public health in general, but the main thrust was really sex education.

Synonyms

Translations

an attack with a sword
a lunge forward
Japanese: 突き tsuki
force due to propulsion
(figurative) primary effort

Verb

  1. To make advance with force.
    We thrust at the enemy with our forces.
  2. To force something upon someone.
    I asked her not to thrust the responsibility on me.
  3. To push out or extend rapidly or powerfully.
    He thrust his arm into the icy stream and grabbed a wriggling fish, astounding the observers.

Synonyms

Translations

make an advance with force
force something upon someone
push out or extend rapidly or powerfully

Extensive Definition

Thrust is a reaction force described quantitatively by Newton's Second and Third Laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a proportional but opposite force on that system.

Examples

A fixed-wing aircraft generates forward thrust when air is pushed in the opposite direction of flight. This can be done in several ways including by the spinning blades of a propeller, or a rotating turbine pushing air out the back of a jet engine, or by ejecting hot gases with a rocket engine. The forward thrust is proportional to the mass of the airstream multiplied by the velocity of the airstream. Reverse thrust can be generated to aid braking after landing by reversing the pitch of variable pitch propeller blades, or using a thrust reverser on a jet engine. Rotary wing aircraft and thrust vectoring V/STOL aircraft use engine thrust to support the weight of the aircraft, and vector some of this thrust fore and aft to control forward speed.
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 equal and opposite direction to the sum of the momentum change in the water flowing through the propeller.
A rocket's mass is propelled forward by a thrust force equal to, and opposite of, the time-rate of momentum change of the exhaust mass accelerated from the combustion chamber through the rocket engine nozzle. This is the exhaust velocity with respect to the rocket, times the time-rate at which the mass is expelled, or in mathematical terms:
T=v\frac
where:
T = thrust generated (force),
\frac = rate of change of mass with respect to time (fuel burn rate).
v = exhaust velocity.
Of course, for a launch the thrust at lift-off should be more than the weight, and with a fair margin, because a "slow launch" would be very inefficient.
Each of the three Space shuttle main engines can produce a thrust of 1.8 MN, and each of its two Solid Rocket Boosters 14.7 MN, together 39.4 MN. Compare with the mass at lift-off of 2,040,000 kg, hence a weight of 20 MN.
By contrast, the simplified Aid for EVA Rescue (SAFER) has 24 thrusters of 3.56 N each.
In the air breathing category, the AMT-USA AT-180 jet engine developed for radio-controlled aircraft produce 90 N (20 Lbf) of thrust. The GE90-115B engines fitted on the Boeing 777-300ER, recognized by the Guinness Book of World Records as the "World's Most Powerful Commercial Jet Engine," have a tested thrust of 569 kN (127,900 lbf).

References

See also

thrust in Arabic: دفع
thrust in German: Schub
thrust in Spanish: Empuje
thrust in Persian: رانش
thrust in French: Poussée
thrust in Korean: 추력
thrust in Italian: Spinta
thrust in Hebrew: דחף (כוח)
thrust in Dutch: Stuwkracht
thrust in Japanese: 推力
thrust in Polish: Ciąg silnika lotniczego
thrust in Russian: Тяга (самолёт)
thrust in Sicilian: Ammuttata
thrust in Simple English: Thrust
thrust in Finnish: Työntövoima

Synonyms, Antonyms and Related Words

acceleration, actuate, advance, advance against, advance upon, afterburner, aggressiveness, animate, assault, atomic power, bang, bear, bear down upon, bear upon, bearing, best part, better part, body, boost, bowl, buck, bulk, bull, bulldoze, bump, bump against, bunt, burden, butt, butt against, cast, charge, chuck, clap, clout, compel, compulsion, core, counterattack, cram, crowd, cut, dash, dig, drive, drive on, driving force, elbow, electric power, electropower, embed, energy, enterprise, essence, exhaust, feint, fire, flank, fling, force, force upon, forward, fuel, gas, generality, get-up-and-go, getaway, ginger, gist, give an impetus, give momentum, goad, gravamen, head, home thrust, horsepower, hurl, hurtle, hustle, hydraulic power, hydroelectric power, impale, impel, impellent, impelling force, impetus, impose on, impose upon, impulse, impulsion, incentive, incite, incitement, infiltrate, initiative, irresistible force, jab, jam, jet power, jet propulsion, jog, joggle, jolt, jostle, kick, launch an attack, line of flight, liquid oxygen, lunge, main body, major part, majority, manpower, march against, march upon, mass, meat, moment, momentum, most, motivate, motive power, mount an attack, move, nuclear power, nudge, open an offensive, pass, pedal, pep, pepper, pickup, pierce, pile drive, piss and vinegar, piston power, pith, pizzazz, plank, plop, plump, plunge, plunk, plurality, poke, pole, poop, power, press, press on, press upon, pressure, prod, propel, propellant, propelling, propelment, propulsion, propulsion charge, pulsion, punch, purport, push, pushing, put, put in motion, quickening, ram, ram down, rattle, reaction propulsion, rocket power, rocket propulsion, roll, row, run, run against, sense, set agoing, set going, set in motion, shake, short, shoulder, shove, shoving, shunt, sink, slap, snap, solar power, speedup, spunk, stab, starch, steam power, step-up, stick, stress, strike, substance, sweep, sweep along, swing, tamp, thermonuclear power, throw, thrust upon, toss, treadle, troll, trundle, upshot, urge, urge on, urge upon, verve, vim, water power, whip on, zing, zip
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