Forces And Energy
Gbogbo ọrọ náà
Lift a bag of rice onto a shelf and you have just paid a bill. The bag was low down and now it is high up, and the difference between those two situations cost you something real. Let the same bag fall and it arrives at the floor moving fast enough to burst, so whatever you paid has clearly not vanished: it was stored on the way up and handed back on the way down. Physics measures both the paying and the storing in one unit, the joule, and this lesson is where you learn to put numbers into that idea.
You will meet three relationships and nothing more. One prices the energy stored when something is raised, one prices the energy carried by something that is moving, and one tells you how quickly a machine can move energy from one of those places to another. Between them they explain why a hoist motor is rated in kilowatts, why a reservoir on a hilltop is a battery made of water, and why the same lift done twice as fast needs twice the power. Every one of the three is printed in the specification's own equation sheet, so the marks here are never for reciting them: they are for knowing which one the question wants and substituting into it cleanly.
Ebumnobi
- An object gains gravitational potential energy when it is raised vertically because work is done against the gravitational force. The relationship between gravitational potential energy, Ep , mass, m, gravitational field strength, g, and height, h, is:
- The kinetic energy of a moving object depends on its mass and its velocity. The relationship between kinetic energy, Ek , mass, m and velocity, v, is:
- Power is the rate at which energy is transferred or the rate at which work is done. The relationship between power, P, work done, W, or energy transferred, E, and time, t, is: and
Maapụ uche
E seela isiokwu a ka ị hụ otu echiche si ejikọta.
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Akwụkwọ Ọmụmụ
Ndetu Nkuzi Zuru Ezu di na Ngwa Green Bridge
Nweta ngwa Green Bridge CBT na ekwenti gi ma o bu kompiuta maka ulo akwukwo IGCSE zuru oke: akwukwo ule ndi gara aga, usoro nyocha, eserese uche, kaadi omumu na nkuzi olu.
Nnyocha Ọmụmụ
Ekele diri gi maka imecha ihe karịrị na Forces And Energy. Ugbu a na ị na-enyochakwa isi echiche na echiche ndị dị mkpa, ọ bụ oge iji nwalee ihe ị ma. Ngwa a na-enye ụdị ajụjụ ọmụmụ dị iche iche emebere iji kwado nghọta gị wee nyere gị aka ịmata otú ị ghọtara ihe ndị a kụziri.
Ị ga-ahụ ngwakọta nke ụdị ajụjụ dị iche iche, gụnyere ajụjụ chọrọ ịhọrọ otu n’ime ọtụtụ azịza, ajụjụ chọrọ mkpirisi azịza, na ajụjụ ede ede. A na-arụpụta ajụjụ ọ bụla nke ọma iji nwalee akụkụ dị iche iche nke ihe ọmụma gị na nkà nke ịtụgharị uche.
Jiri akụkụ a nke nyocha ka ohere iji kụziere ihe ị matara banyere isiokwu ahụ ma chọpụta ebe ọ bụla ị nwere ike ịchọ ọmụmụ ihe ọzọ. Ekwela ka nsogbu ọ bụla ị na-eche ihu mee ka ị daa mba; kama, lee ha anya dị ka ohere maka ịzụlite onwe gị na imeziwanye.
- A crate of mass 40 kg is raised through a vertical height of 2.5 m. The gravitational field strength is 9.8 N/kg. How much gravitational potential energy does it gain? A. 100 J B. 392 J C. 980 J D. 1960 J Answer: C
- A machine transfers 3000 J of energy in 15 s. What is its output power? A. 0.005 W B. 200 W C. 2000 W D. 45 000 W Answer: B
- A ball of mass 0.50 kg travels at 6.0 m/s. What is its kinetic energy? A. 1.5 J B. 3.0 J C. 9.0 J D. 18 J Answer: C
- Which of these is the unit of power? A. The joule B. The newton C. The watt D. The newton per kilogram Answer: C
- A motor transfers energy at a rate of 250 W. How much energy does it transfer in 2.0 minutes? A. 125 J B. 500 J C. 3000 J D. 30 000 J Answer: D
Rue ajuju ndi a n'ime ngwa ahu
Rue ajuju ndi a n'ime ngwa ahu
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Meecha Ajụjụ Ule Ọmarịcha
Ị chọrọ ime ajụjụ ule ọmarịcha gbasara Forces And Energy? Budata ngwa Green Bridge CBT iji nweta ajụjụ ule ọmarịcha na nyocha zuru ezu gbasara isiokwu a.
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