Mohlala oa potso ea puisano mabapi le ho eketsa lebelo
Lebelo ke mohopolo oa motheo fisiks, haholo-holo kinematics, lekala la fisiks le ithutang motsamao oa lintho ntle le ho nahana ka sesosa sa motsamao oo. Khopolo ena ha e amane feela le thuto empa hape le lits'ebetsong tsa letsatsi le letsatsi tse kang boenjiniere, lipapali le lipalangoang. Sehlooho sena se tla tšohla mehlala e 'maloa ea mathata a amanang le lebelo, a felletseng ka litlhaloso tsa mohato ka mohato ho thusa kutloisiso.
Khopolo ea Motheo ea Keketseho ea Lebelo
Pele re kena lipotsong tsa mohlala, ho ka ba molemo hore re hopole likhopolo tse ling tsa motheo mabapi le lebelo le ho potlaka.
1. Lebelo (v) le hlalosoa e le phetoho boemong ka nako ea yuniti.
2. Ho potlaka (a) ke bongata bo bolelang phetoho ya lebelo ka yuniti ya nako.
Foromo ea motheo ea ho potlakisa ke:
\[ a = \frac{\Delta v}{\Delta t} \]
Moo:
– \( a \) ke ho potlaka,
– \( \Delta v \) ke phetoho ea lebelo,
– \( \Delta t \) ke nako e pakeng tsa nako.
Mohlala oa Potso ea 1
Potso:
Qalong koloi e tsamaya ka lebelo la 10 m/s. Kamora metsotsoana e 5, lebelo la koloi le ba 20 m/s. Potlako e tloaelehileng ea koloi ke efe?
Puisano:
Hoa tsebahala:
– Lebelo la pele (\( v_0 \)) = 10 m/s,
– Lebelo la ho qetela (\( v_f \)) = 20 m/s,
– Nako (\( \Delta t \)) = 5 s.
Re ka sebelisa foromo ea ho potlakisa:
\[ a = \frac{v_f – v_0}{\Delta t} \]
Kenya mekhoa e tsebahalang sebakeng sa eona:
\[ a = \frac{20 – 10}{5} \]
\[ a = \frac{10}{5} \]
\[ a = 2 \, \mongolo{m/s}^2 \]
Kahoo, karolelano ea lebelo la koloi ke 2 m/s².
Mohlala oa Potso ea 2
Potso:
Terene e qala ho tloha phomolong mme e fihla lebelo la 30 m/s ka metsotsoana e 10. Bala karolelano ea ho potlaka ha eona le sebaka se tsamailoeng nakong eo.
Puisano:
Ho potlaka:
Hoa tsebahala:
– Lebelo la pele (\( v_0 \)) = 0 m/s (hobane le qala ho tloha boemong bo sa sisinyeheng),
– Lebelo la ho qetela (\( v_f \)) = 30 m/s,
– Nako (\( \Delta t \)) = 10 s.
Ho sebelisa foromo ea ho potlakisa:
\[ a = \frac{v_f – v_0}{\Delta t} = \frac{30 – 0}{10} = 3 \, \text{m/s}^2 \]
Sebaka se tsamailoeng:
Ho bala sebaka (\( s \)) se tsamailweng, re ka sebedisa e nngwe ya di-kinematic equation:
\[ s = v_0 t + \frac{1}{2} ho^2 \]
Kenya mekhoa e tsebahalang sebakeng sa eona:
\[ s = 0 \cdot 10 + \frac{1}{2} \cdot 3 \cdot (10)^2 \]
\[ s = \frac{1}{2} \cdot 3 \cdot 100 \]
\[ s = 150 \, \mongolo{m} \]
Kahoo, sebaka se tsamauoang ke terene ke limithara tse 150.
Mohlala oa Potso ea 3
Potso:
Sethuthuthu se eme sebakeng se itseng 'me se qala ho tsamaea ka lebelo le sa khaotseng la 4 m/s². Kamora ho tsamaea metsotsoana e 8, lebelo la ho qetela le sebaka se tsamauoang ke sethuthuthu ke sefe?
Puisano:
Lebelo la ho qetela:
Hoa tsebahala:
– Lebelo la pele (\( v_0 \)) = 0 m/s (hobane le qala ho tloha boemong bo sa sisinyeheng),
– Ho potlaka (\( a \)) = 4 m/s²,
– Nako (\( t \)) = 8 s.
Ho sebelisa foromo ea lebelo:
\[ v_f = v_0 + ho \]
Kenya mekhoa e tsebahalang sebakeng sa eona:
\[ v_f = 0 + 4 \cdot 8 \]
\[ v_f = 32 \, \mongolo{m/s} \]
Sebaka se tsamailoeng:
Ho sebelisa foromo ea hole:
\[ s = v_0 t + \frac{1}{2} ho^2 \]
Kenya mekhoa e tsebahalang sebakeng sa eona:
\[ s = 0 \cdot 8 + \frac{1}{2} \cdot 4 \cdot (8)^2 \]
\[ s = \frac{1}{2} \cdot 4 \cdot 64 \]
\[ s = 128 \, \mongolo{m} \]
Kahoo, kamora ho tsamaya metsotsoana e 8, lebelo la ho qetela la sethuthuthu ke 32 m/s mme sebaka seo se se tsamaileng ke limithara tse 128.
Mohlala oa Potso ea 4
Potso:
Bolo e lahlelwa hodimo ka lebelo la pele la 20 m/s. Kamora ho fihla ntlheng ya yona e hodimo, bolo e kgutlela fatshe ka lebelo le phahameng ka lebaka la matla a kgoheli \( g = 9.8 \, \text{m/s}^2 \). Ho nka nako e kae hore bolo e fihle fatshe hape?
Puisano:
Nako eo ho e nkang ho nyoloha le ho theoha e tšoana. Kahoo re hloka feela ho bala nako eo ho e nkang ho nyoloha, ebe re e atisa ka 2 ho fumana kakaretso ea nako.
Hoa tsebahala:
– Lebelo la pele (\( v_0 \)) = 20 m/s,
– Lebelo ntlheng e phahameng ka ho fetisisa (\( v_f \)) = 0 m/s (hobane e ema motsotsoana),
– Ho potlaka ka lebaka la matla a khoheli (\(g \)) = 9.8 m/s².
Ho sebelisa foromo ea lebelo:
\[ v_f = v_0 + (-g) t \]
Kenya mekhoa e tsebahalang sebakeng sa eona:
\[0 = 20 – 9.8 t \]
\[ 9.8 t = 20 \]
\[t = \frac{20}{9.8} \]
\[t \hoo e ka bang 2.04 \, \mongolo{s} \]
Ena ke nako ea hore bolo e fihle ntlheng ea eona e phahameng ka ho fetisisa. Kahoo, nako eohle ea ho phahama le ho theoha ke:
\[ 2 \cdot 2.04 \hoo e ka bang 4.08 \, \text{s} \]
Kahoo, nako yohle e nkuwang hore bolo e fihle fatshe hape ke metsotsoana e ka bang 4.08.
Qetello
Mathata ohle a tšohliloeng ka holimo, mohato oa mantlha ke ho utloisisa likhopolo tsa motheo tsa lebelo le ho potlaka le hore na li sebelisoa joang liforomong tse itseng. Leha mathata a fapana, mokhoa ona o latela melao-motheo ea motheo ea fisiks. Ho tšeptjoa hore ka ho itloaetsa mathata ana, baithuti ba tla fumana kutloisiso e tebileng ea hore na lebelo le ho potlaka li sebelisana joang motsamaong oa lintho.
Ehlile, lits'ebetsong tsa letsatsi le letsatsi, ho utloisisa mohopolo ona ho ka ba molemo haholo, eseng feela lithutong tsa thuto empa hape le mafapheng a fapaneng a litsebi joalo ka boenjiniere, lipalangoang le tse ling. Kamehla hopola ho utloisisa bothata pele, pele u leka ho bo rarolla, e le hore mokhoa oa ho utloisisa le ho rarolla bothata o be bonolo le o sebetsang haholoanyane.
