Forces (continued)
Akopọ
Push a door near its handle and it swings open easily; push near the hinge and it barely moves. That everyday difference is the turning effect of a force, or moment, and it explains spanners, see-saws, cranes and why a wide base stops you toppling over.
In this lesson you will meet friction and drag, define and calculate the moment of a force, apply the principle of moments to balance a beam, and use the centre of gravity to judge whether an object is stable. These ideas turn into reliable marks once you practise the calculations.
Awọn Afojusun
- Describe solid friction as the force between two surfaces that may impede motion and produce heating
- Know that friction (drag) acts on an object moving through a liquid
- Know that friction (drag) acts on an object moving through a gas (e.g. air resistance)
- Describe the moment of a force as a measure of its turning effect and give everyday examples
- Define the moment of a force as moment = force × perpendicular distance from the pivot; recall and use this equation
- Apply the principle of moments to situations with one force each side of the pivot, including balancing of a beam
- State that, when there is no resultant force and no resultant moment, an object is in equilibrium
- State what is meant by centre of gravity
- Describe an experiment to determine the position of the centre of gravity of an irregularly shaped plane lamina
- Describe, qualitatively, the effect of the position of the centre of gravity on the stability of simple objects
- [Supplement] Apply the principle of moments to other situations, including those with more than one force each side of the pivot
- [Supplement] Describe an experiment to demonstrate that there is no resultant moment on an object in equilibrium
Ẹ̀kọ́ Ohùn
Gbọ́ ẹ̀kọ́ yìí nínú áàpù
Àwòrán ọpọlọ
A ti ṣe àwòrán kókó yìí kí o lè rí bí àwọn èrò ṣe so pọ̀.
Ṣí àwòrán ọpọlọ nínú áàpù
Káàdì ìrántí
Ìdánrawò kíákíá lórí ohun tí wọ́n ń dán wò nínú kókó yìí.
Ṣe ìdánrawò káàdì wọ̀nyí nínú áàpù
Akọ̀wé Ẹ̀kọ́
Àkọsílẹ̀ Ẹ̀kọ́ Pípé wà lórí Ohun Èlò Green Bridge
Gba ohun èlò Green Bridge CBT sórí fóònù tàbí kọ̀mpútà rẹ fún gbogbo ilé ìkàwé IGCSE: ìwé ìdánwò àtijọ́, ìlànà ìdíwọ̀n, àwòrán èrò, káàdì ìkẹ́kọ̀ọ́ àti ẹ̀kọ́ ohùn.
Ìdánwò Ẹ̀kọ́
Oriire fun ipari ẹkọ lori Forces (continued). Ni bayi ti o ti ṣawari naa awọn imọran bọtini ati awọn imọran, o to akoko lati fi imọ rẹ si idanwo. Ẹka yii nfunni ni ọpọlọpọ awọn adaṣe awọn ibeere ti a ṣe lati fun oye rẹ lokun ati ṣe iranlọwọ fun ọ lati ṣe iwọn oye ohun elo naa.
Iwọ yoo pade adalu awọn iru ibeere, pẹlu awọn ibeere olumulo pupọ, awọn ibeere idahun kukuru, ati awọn ibeere iwe kikọ. Gbogbo ibeere kọọkan ni a ṣe pẹlu iṣaro lati ṣe ayẹwo awọn ẹya oriṣiriṣi ti imọ rẹ ati awọn ogbon ironu pataki.
Lo ise abala yii gege bi anfaani lati mu oye re lori koko-ọrọ naa lagbara ati lati ṣe idanimọ eyikeyi agbegbe ti o le nilo afikun ikẹkọ. Maṣe jẹ ki awọn italaya eyikeyi ti o ba pade da ọ lójú; dipo, wo wọn gẹgẹ bi awọn anfaani fun idagbasoke ati ilọsiwaju.
- The moment of a force is calculated using: A. force / distance B. force x perpendicular distance C. force + distance D. force x time Answer: B
- A force of 25 N acts 0.40 m from a pivot. The moment is: A. 0.016 N m B. 10 N m C. 62.5 N m D. 25.4 N m Answer: B
- An object is in equilibrium when: A. it is moving fast B. there is no resultant force and no resultant moment C. only the forces balance D. only the moments balance Answer: B
- An object is most stable when it has: A. a high centre of gravity and narrow base B. a low centre of gravity and wide base C. a high centre of gravity and wide base D. a low centre of gravity and narrow base Answer: B
- Drag on a moving object: A. is constant at all speeds B. increases as speed increases C. acts in the direction of motion D. only acts in liquids Answer: B
Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà
Ṣiṣẹ́ lórí àwọn ìbéèrè wọ̀nyí nínú ohun èlò náà
Awọn Iwe Itọsọna Ti a Gba Nimọran
Ẹ̀kọ́ síwájú láti àwọn orísun ṣíṣí
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Abala ìwé ẹ̀kọ́
Stability
It is one thing to have a system in equilibrium; it is quite another for it to be stable. The toy doll perched on the man’s hand in Figure 9.9 , for example, is not in stable equilibrium. There are three types of equilibrium : stable , unstable , and neutral . Figures throughout this module illustra
"College Physics: Stability" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/9-3-stability. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
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Abala ìwé ẹ̀kọ́
Drag Forces
Another interesting force in everyday life is the force of drag on an object when it is moving in a fluid (either a gas or a liquid). You feel the drag force when you move your hand through water. You might also feel it if you move your hand during a strong wind. The faster you move your hand, the h
"College Physics: Drag Forces" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/5-2-drag-forces. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
Àwọn àjọ mìíràn ló tẹ̀ wọ́n jáde lábẹ́ ìwé àṣẹ ṣíṣí, a sì dá wọn lọ́lá bí wọ́n ṣe béèrè. Àwọn ìjápọ̀ ń ṣí ojú òpó wọn.
Ṣe Adaṣe Awọn Ibeere Idanwo Adaṣe
Ṣe o fẹ ṣe adaṣe awọn ibeere idanwo adaṣe nipa Forces (continued)? Ṣe igbasilẹ ohun elo Green Bridge CBT lati wọle si awọn ibeere idanwo adaṣe ati awọn ayẹwo adaṣe kikun fun koko-ọrọ yii.
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