5 Motsamao oa parabolic Mosebetsi le matla a kinetic Motsamao o otlolohileng Motsamao o otlolohileng le o otlolohileng Mathata le Litharollo
1. Bolo e lahlelwa ho tloha hodimo ho moaho ka lebelo la pele la 8 m/s ka sekhutlo sa 20 o ka tlase ho se rapameng. Bolo e otla fatshe metsotswana e 3 hamorao.
a) Bolo e ama fatshe hole hakae ho tloha tlase ho moaho
b) Bolo e lahleloa holimo hakae ho tloha sebakeng seo
c) Bolo e fihla bolelele ba limithara tse 10 ho tloha moo e lahlelwang teng
vox = vo Cos 20o = 8 (0.939) = 7.512 m/s
v oy = v o sebe 20 o = 8 (0.342) = 2.736 m/s
a) x
Metsamao e otlolohileng e hlahlojoa e le motsamao o ts'oanang oa mola, kahoo ho sebelisitsoe mokhoa oa ho tsamaisa motsamao o ts'oanang oa mola.
x = v ox t
x = (7.512 m/s)(3 s)
x = 22.536 m
b) y
Metsamao ea tataiso e otlolohileng e sekasekoa e le motsamao oa ho oa ka bolokolohi ho sebelisoa mokhoa oa motsamao oa ho oa ka bolokolohi.
Sebelisa foromo ena y = vot + ½ gt 2
Motsamaong oa ho oa ka bolokolohi, v o = 0 kahoo foromo e fetoha: y = ½ gt 2
y = ½ (9.8)(3 2 )
y = (4.9)(9)
y = 44 m
c) y = 10 m
Sebelisa foromo y = ½ gt 2
10 = ½ (9,8) t 2
10 = 4.9 t 2
t 2 = 10 / 4.9
t 2 = 2
t = 1.4 s
2. Sehlopha sa terene ea lintja se hula boima ba 100 kg ho fihlela ho 2 km ka holim'a bokaholimo bo bataletseng ka lebelo le sa fetoheng. Haeba coefficient ea khohlano pakeng tsa terene le lehloa e le 0.15, fumana:
a) mosebetsi o entsoeng ke ntja
Bala lipalo tsa khohlano ea kinetic:
F k = µ k N = µ k w = µ k mg = (0.15) (100 kg) (9.8 m/s 2 ) =147 N
Lebelo la boima lea tsitsitse kahoo, ho ea ka molao oa Newton, matla a hlahang = 0. Kahoo F k = F = 147 N
Mosebetsi o entsoeng ke ntja:
W = F d = (147 N)(2000 m) = 294,000 J
b) Matla a lahlehang ke khohlano
Matla a lahlehang ke khohlano:
Mosebetsi = matla, kahoo:
W = F k d = (147 N)(2000 m) = 294,000 J
3. Matla a rapameng a 150 N a sebediswa ho sutumelletsa lebokose dimithara tse 6 ka hodima bokahodimo bo makukuno. Haeba lebokose le tsamaya ka lebelo le sa fetoheng:
a) Mosebetsi o entsoeng ka matla a 150 N
W = F d = (150 N) (6 m) = 900 J
b) Matla a lahlehang ka lebaka la khohlano
Lebokose le tsamaea ka lebelo le sa fetoheng hoo matla a hlahang a sebetsang lebokoseng = 0.
Kahoo, matla a rapameng = 150 N = khohlano ea kinetic.
Matla a lahlehang ka lebaka la khohlano:
W = F ks = (150 N)(6 m) = 900 J
c) Palo e lekanang ea khohlano ea kinetic
Mokhoa oa matla a khohlano:
F k = µ k N = µ k w = µ k mg
150 = µ km m (10)
15 = µ km m
µ k = 15/m
m = boima ba lebokose
µ k = coefficient ea khohlano ea kinetic
Khohlano ea kinetic e sebetsa ha lintho li tsamaea, khohlano e sa fetoheng e sebetsa ha lintho li ntse li eme.
4. Karoloana e na le lebelo (3i-4h) m/s. Fumana karolo ea momentum ho x le y-axis le boholo ba momentum.
Lebelo ho x-axis: 3 m/s
Lebelo ho y-axis: 4 m/s
Motsamao ho x-axis: mv = 3 m
lebelo mothating oa y: mv = 4 m
Boholo ba lebelo:
leq 2 = (3 m) 2 + (4 m) 2
leq 2 = 9 m 2 + 16 m 2
leq 2 = 25 m 2
p = 5 m
p ke letšoao la motsamao o otlolohileng.
5. Koloi e potlakiswa ka lebelo le ts'oanang ho tloha ho e sa sisinyeheng ho isa ho 22 m/s ka metsotsoana e 9. Haeba bophara ba thaere e le 58 cm, hlalosa:
a) palo ea lipotoloho tsa mabili nakong ea motsamao (nahana hore ha ho thelle)
Bala ho potlaka ha koloi:
v t = v o + ho
22 = 0 + a 9
22 = 9a
a = 22/9 = 2.44
Bala sebaka:
d = vot + ½ ho 2 = 0 + ½ ho 2
d = ½ ho 2 = ½ (2.44)(9 2 ) = (1.22)(81) = 98.82 m
Sebaka sa koloi = 98.82 metres = 9882 cm
Bophara ba thaere = 58 cm
Palo ea liphetohelo = 9882 cm / 58 cm = 170.38 rev
b) Lebelo la ho qetela la ho potoloha ha thaere ka lebelo/motsotso
Lebelo la ho qetela = limithara tse 22/motsotsoana = 2200 cm/ motsotsoana
1 rev = bophara bo le bong ba thaere = 58 cm
Palo ea liphetohelo:
2200 cm / 58 cm = diphetoho tse 40
Kahoo, lebelo la ho qetela phetohong/motsotso
40 rev/motsotswana = 40 rev / metsotsoana e 60 = 0.67 rev/motsotswana kapa 0.67 rev/motsotswana
