Information about Moments couples levers

PowerPoint to teach moments, couples & levers

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Moments and levers Definition Principle of moments Couples Calculations Classes Mechanical advantage

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Moment of Force The moment of a force about a point is the PRODUCT of the magnitude of the force and the perpendicular distance from the point to the line of the force. MOMENT = FORCE X DISTANCE = 5 x 0.25 = 1.25 N.m 5 N25 cm

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Calculate the moment of the force, or ……….., due to each force when several forces act on the same object using the equation: = F … r F Calculating Torque F1 F2 = F x r = (F1x …1) + (F2x …2) When calculating torque the ………….of all the PERPENDICULAR FORCES must be used. TORQUE

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Equilibrium For an object to be in equilibrium BOTH the sum of the …………….. acting on the object and the sum of the …………….of the forces must be ZERO. Solve problems involving objects in equilibrium. F2 F3F1 FORCES (Linear) in equilibrium .: F1 + F2 + F 3 = …… MOMENTS in equilibrium .: ……………. a fulcrum. (F1) (F1….) + (F2…..) + (F3……) = 0 x1 x2 If a 60 Kg person stands 2 meters from one end of a 3 meter scaffolding plank what force is needed to support each end of the plank?

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Equilibrium Question F2 (F1. x1) + (F2. x2) + (F3.0) = 0 (F1.1)+((60x10)x2) + (F3x0) = 0 F1 + (1200) + 0 = 0 F1 = -1200 N .: F1 = 1200 N anticlockwise! A 1200 N force is needed at F1 to balance the plank! x1 x2 If a 60 Kg person stands on one end of a 3 meter scaffolding plank what force is needed to support him on the other end of the plank if the plank is balancing on a fulcrum 2m away from the 60kg person? ?? 60kg 2m F3 1 m F1 ?? Sum of all moments = zero Choose clockwise as POSITIVE! F3 = fulcrum

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Levers • Describe the terms “load” and “effort” for a lever • Define “mechanical advantage” as the ratio of “load/effort” and calculate the mechanical advantage for simple levers ………….................. …… ...... .. If in equilibrium: …… x ….. = …… x …..

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Levers • Describe the terms “load” and “effort” for a lever • Define “mechanical advantage” as the ratio of “load/effort” and calculate the mechanical advantage for simple levers LoadEffort e l If in equilibrium: E x e = L x l Mechanical Advantage Load Force Effort Force F E OR = e l == Effort distance Load distance =

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Mechanical Advantage Mechanical Advantage is the RATIO of the LOAD to the EFFORT. Apply the concept of mechanical advantage to everyday situations. Mechanical Advantage Load Force Effort Force N Load L Effort E l e F E OR = e l == Effort distance Load distance =

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Types of Levers Class 1Effort Load Class 2 Effort Load Class 3 Effort Load Load Load Effort Effort o.75 o.25 o.75 o.75 o.25 o.25 Type 1 F in middle MA = e/l= 0.75/0.25 = 3 Type 2 F at end L in middle M.A. = e/l = 1/0.25 = 4 Type 3 F in mid L at end M.A. = e/l = 0.25/0.75 = 0.3 The weight of the lever helps in type 1 but not T2!

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Examples of Levers

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Force Couple A special case of moments is a couple. A couple consists of two parallel forces that are equal in magnitude, opposite in direction and do not act in a straight line but are separated by a distance (d). It does not produce any translation, only rotation. The resultant force of a couple is zero. BUT, the resultant of a couple is not zero; it is a pure moment. Example: A steering wheel of diameter 0.75 m is turned by a force of 20 N applied to each end. Calculate the magnitude of the force couple: Couple = F x d = (20 x 0.75) = 15 N.m F F d d 2 d 2 Couple = Total Turning Moment = (F x d/2) + (F x d/2) = ½ (F x d) + ½ (F x d) = F x d

SAMPLE ONLY SAMPLE ONLY SAMPLE ONLY For FULL presentation click HERE >> ScienceCafe Hi - This is a SAMPLE presentation only. My FULL presentations, which contain loads more slides (with all the gaps filled in) as well as other resources, are freely available on my resource sharing website: www.sciencecafe.org.za (paste into your browser if link above does not work) Have a look and enjoy! Keith Warne

Want to watch this again later? Sign in to add this video to a playlist. An A Level Physics revision video covering Moments, Torques and Levers

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The moment (or torque) of a couple is calculated by multiplying the size of one of the force (F) by the perpendicular distance between the two forces (s).

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Two parallel 60N forces are applied to a lever as shown. Determine the moment of the couple formed by the two forces: a) by resolving each force into ...

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Torque, moment, or moment of force ... resultant moment of a couple". Torque is defined ... Archimedes on levers. The term torque was apparently ...

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MOMENTS, COUPLES, FORCES SYSTEMS & FORCE RESOLUTION (a) Translation (b) Translation & Rotation (c) Rotation ... Lever arm M= - F x d = -25 x 15 = - 375 #-in

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Moments, Couples and Equilibrium A-Level Mechanics revision section looking at Moments, Couples and Equilibrium.

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Simple couple Definition. A couple is a pair of forces, equal in magnitude, oppositely directed, and displaced by perpendicular distance or moment.

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The Principle of Moments. Submitted by Anonymous on Mon, 09/28/2015 - 09:38. Calculating moments. ... Latest Moments, Couples and Equilibrium question. 1 .

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A secondary school revision resource for AQA GCSE Triple Science about physics: Moments

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So to calculate the moment (or torque) due to a couple you can use: Moment = Magnitude of one force x perpendicular distance between the lines of action of ...

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