1. Ibhulokhi elingamakhilogremu angu-2 lilele endizeni ethambekele emaceleni nge-engeli engu-37 o kuya endaweni evundlile. Thola ubukhulu bamandla angaphandle asetshenziswa ebhulokhini, ukuze ibhulokhi lingasheleli phansi endizeni. (sin 37 o = 0.6, cos 37 o = 0.8, g = 10 ms -2 , µ k = 0.2)
Kwaziwa:
Isisindo (m) = 2 kg
Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 m/s 2
Isisindo sebhulokhi (w) = mg = (2)(10) = 20 amaNewton
Isono 37 o = 0.6
I-Cos 37 o = 0.8
I-coefficient ye- kinetic friction (µ k ) = 0.2
Ingxenye ka-y yesisindo (w y ) = w cos 37 o = (20)(0.8) = 16 Newtons
Ingxenye engu-x yesisindo (w x ) = w sin θ = (20)(sin 37) = (20)(0.6) = 12 Newtons
amandla avamile (N) = w y = 16 Newtons
Okufunwayo : Amandla angaphandle (F)
Isixazululo :
wx = 12 uNewton
Amandla okungqubuzana kwe-kinetic (f k ) = µ k N = (0.1)(16) = 1.6 AmaNewton
Ubukhulu bamandla angaphandle u-F asetshenziswe ebhulokini :
F + f k – w x = 0
F = w x – f k
F = 12 – 1.6
F = 10.4 Newton
Amandla angaphandle u-F makhulu kune-10.4 Newtons.
[irp]
2. Isisindo sebhulokhi = 2 kg, i-coefficient of static friction µ s = 0.4 kanye no-θ = 45 o . Thola ubukhulu bamandla F ukuze ibhulokhi iqale ukushelela phezulu.
Kwaziwa:
I-coefficient yokungqubuzana okungaguquki (µs ) = 0.4
I-engeli (θ) = 45 o
Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 m/s 2
Isisindo sebhulokhi (m) = 2 kg
Isisindo sebhulokhi (w) = mg = (2 kg)(10 m/s 2 ) = 20 kg m/s 2 = 20 Newtons
Ingxenye engu-x yesisindo (w x ) = w sin θ = (20)(sin 45) = (20)(0.5√2) = 10√2 AmaNewton
Ingxenye engu-y yesisindo (w y ) = w cos θ = (20)(cos 45) = (20)(0.5√2) = 10√2 AmaNewton
Okufunwayo : Ubukhulu bamandla F
Isixazululo:
Ibhulokhi iqala ukushelela phezulu, uma F ≥ wx + fs.
Ingxenye yesisindo engu-x:
w x = 10√2 Newton
ingxenye engu-y yesisindo :
w y = 10√2 Newton
Amandla avamile :
N = w y = 10√2 Newton
Amandla okungqubuzana okungaguquki :
f s = µ s N = (0,4)(10√2) = 4√2
Ubukhulu bamandla F ukuze ibhloko liqale ukushelela phezulu :
F ≥ w x + f s
F ≥ 10√2 + 4 √2
F ≥ 14√2 Newton
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