Physics: Energy, work

A wannan makala zamu yi bayani ne akan energy da kuma work. Game da wannan darasi abubuwan da ake so dalibai su lura da su sune, energy, work, types of energy, sources of energy, classification of sources of energy, law of conservation of energy da mathematical problems.

Mene ne energy?

Energy a Turance na nufin, ability or capacity to do work, kuma energy is a scalar quantity. Sannan S. I unit na shi, shi ne joule (J). A wani bangaren kuma work a kimiyyar physics ana samun sa ne idan aka yi multiplying na force da displacement.

A Turance, work is defined as the product of force and displacement and always move in the direction of the force.  S. I Unit na work daya ne da na energy wato Joule (J)

Ire-iren energy (types of energy)

Energy ya na da nau’uka daban-daban, ga su kamar haka:

1. Mechanical energy: Wannan nau’i na energy ya rabu gida biyu, potential da kuma kinetic energies, ana samun su ne a sanadiyar ayyukan dan adam.
2. Kinetic energy ya na da fomula kamar haka K.E =
3. Potential energy ya na da fomula kamar haka P.E = mgh ko kuma k
4. Chemical energy:  Ana samun shi ne daga abinci da muke ci da kuma sauran chemicals da ake yi a laboratory.
5. Solar energy: Ana samun shi ne daga ranan da ke iso mu daga sama.
6. Heat energy: Shi wannan ana samun shi ne da ga zafin rana, zafin wutar murhu ko zafi daga dutsen guga da sauransu
7. Sound energy: Ana samun shi ne da sautuka da muke fitarwa.
8. Electrical energy: Ana samun shi ne idan electrons suna tafiya wanda mun fi  sanin shi da wutan NEPA.
9. Nuclear energy: Wannan nau’i na energy kuma ana samun shi a cikin nucleus na atom.

Karin bayani game da kinetic da potential energies

Misalan abubuwa da ake danganta su da kinetic energy su ne kamar haka,

1.  A rolling ball
2.  An object falling under gravity
3. Wind or air in motion
4. A bullet movement
5. An athlete running a race
6. A plane flying.

Potential energy a Turance is the energy of a body due to its position, while Kinetic energy is the energy of a body due to its motion.

Exercise 1:

1. Define Energy
2. What is the S.I Unit of work
3. Differentiate between potential and kinetic energy.

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Law of conservation of energy

Kamar yadda muka gani a bayananmu da suka shude, energy na da nau’uka daban-daban, abinda ba mu fada ba shi ne ana iya canza ko wani nau’i zuwa wani/wasu, nau’in/nau’ukan ba tare da an samu raguwan energy ba.

Ga law dinnan a Turance kamar haka, It states that energy can neither be created nor destroyed but can be converted from one form to the other.

Misali na farko:

A ball of mass 8kg falls from rest from a height of 100m. Neglecting air resistance, calculate its kinetic energy after falling a distance of 30m. (take g as 10ms )

Amsa:

Da farko sai mu fitar da abubu wan da aka bamu daga cikin tambayan

Mass, m = 8kg,

Velocity na farko wato (lokacin da h = 100m) u = 0ms ,

Distance moved (nisan tsawon tafiya) h = 30m,

g = 10ms ,

Amma velocity a wannan tsawon v = ?

 K.E = ? shima, idan zamu samo v, sai mu yi amfani da wannan fomula v = u + 2gh

v = 0 + (2×10×30) = 600

v = = 24.49 ms ,

Amma mun sani cewa K.E = anan sai mu saka numbobin su kamar yadda ya ke a formula

K.E = = × 8 × 600 = 4 × 600 = 2400j kamar yadda aka bukata. Haka kuma shi

K.E = Potential energy loss = Δmgh = 8×10×30 = 2400j

Misali na biyu:  

A body of mass 100kg is released from a height of 200m. With what energy does the body strike the ground?  (g = 10ms )

Amsa:

Anan kuma zamu ga an bamu mass, m = 100kg, tsawo (height), h = 200m da kuma g =10ms ana son mu nemo P.E = ? Tunda mun san

P.E = mgh = 100×10×200 =200000j

Misali na uku:

A stone of mass 50kg is moving with a velocity of 20m/s. Calculate the kinetic energy.

Amsa:

Da farko sai mu fitar da abubuwa da aka bamu kamar haka,

Mass, m = 50kg,

Velocity, v =20m/s.

K.E = ?  Sai mu yi anfani da wannan fomula

K.E = = × 50 × (20)  = 25 × 400 = 10000J

EXERCISE 2:

A ball of mass 1kg is dropped from a height of 5m and bounces to a height of 10m. Calculate (i) its kinetic energy just before impact. (ii) its initial bouncing velocity and kinetic energy

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Sources of energy

Kamar yadda muka yi bayani da farko cewa energy na nan nau’ uka daban-daban ko wani nau’i zamu iya cewa ya samu ne daga dayan wadannan;

1. Energy from the sun (solar energy),
2. Wood (firewood),
3. Coal,
4. Electricity,
5. Fossil fuels,
6. Chemicals kamar yadda suke a cikin cells da batteries.

Kuma wadannan sources na energy din an sake raba su zuwa, renewable energy resources da kuma non-renewable energy resources

Renewable energy resources: A Turance, these sources are not usually depleted as a result of usage. E.g , solar energy, tidal waves, wind, waterfalls and dams. Wannan na nufin shi wannan renewable energy din duk yadda aka yi amfani da shi baya karewa gaba daya.

Non-renewable energy resources : A Turance, these sources are usually reduced as they are being used. E.g fossil fuels, coal, oil, natural gas and wood. Wannan kuma na nufin cewa idan aka yi anfani da su da yawa suna karewa gaba daya.

Amfanin energy a gurin dan adam (Uses of energy)

Kamar yadda kuka gani daga farko munce energy na da nau’uka da yawa, haka kuma ko wanne na da irin amfaninsa. Ga bayanin su kamar haka:

1. Solar energy is a universal source of light to planet earth. The plants also use it to manufacture their own food through photosynthesis. Wato solar energy shi ke ba da haske ga duniya baki daya kuma plants wato tsirrai suna amfani da wannan haske su samarwa kansu abinci don su girma ta wani hanya da ake kira PHOTOSYNTHESIS.
2. Firewood gives heat for cooking our food. Itace da muke hura wutan dafa abinci yana bada heat energy wanda shi ne yake bada dama abinci ya dafu.
3. Energy from coal is used to boil water, then, produce steam used in steam engines. Kamar yadda muka gani shi coal ma’adani ne da ake anfani da shi gurin tafasa ruwa domin samo STEAM wanda ake anfani da shi a steam engine. Kuma da shine jirgin kasa yake anfani.
4. Energy from waterfalls is used in hydro-electric power stations like ka‘inji dam to produce electricity. A wannan kuma ana anfani da manyan dam na ruwa ayi producing na electricity.
5. Natural gas, petroleum, diesel oil, e.t.c are all derived from fossil fuels. Su wadanna duka ana samun su ne yayin da dotti da muke zubarwa da ciyayi da ganyen itatuwa da suka rube, ruwan sama ya tattare su ya tara su a karkashin kasa, idan suka kai wani adadin shekaru me tsawo sai su canja zuwa wadannan. Muna amnfani da su a motocin mu dama sauransu.
6. Chemical energy from cells and batteries are used to power our electronics and phones. Chemicals da ake yin su a laboratories na amfani da su ne a toshi, battery na mota da sauran su don su taimaka.

The impact of energy usage on the environment

Amfani da muke yi da energy a guraren zaman mu yana jawo abubuwa da za su taimaka mana da ma kuma abubuwa da za su cutar da mu. Abubuwan da za su kasance masu anfani a gare mu sune haske da zamu rika gani idan akwai ELECTRICTY, saukin tafiye-tafiye da sauran su. Amma abubuwan da za su zama masu cutar da mu kuma su hada da waste na radiation daga nuclear reactor,  gurbacecciyan ruwan sha daga OIL SPILLAGE, global warming ,  green house effect .

EXERCISE 3:

1. If the maximum speed of a pendulum bob is 4.5m/s at the lowest point O, calculate the

Height, h of the pendulum bob above O where its velocity is zero.

• Define the following terms:
• Work  
• Energy
• kinetic energy
• potential energy.