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કણોના તંત્રનુ ડાઇનેમિક્સ

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ભૌતિક વિજ્ઞાન ધોરણ 11 સેમિસ્ટર 2

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ભૌતિક વિજ્ઞાન

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2400 kgની એક બસ સીધા રસ્તા પર્ 60 km/hની ઝડપથી જાય છે. બસની પાછળ 1600 kgની એક કાર 80 km/h ની ઝડપથી આવી રહી છે. બંને વાહનોનુ દ્રવ્યમાન-કેન્દ્ર કેટલી ઝડપથી ગતિ કરતું હશે ?

  • 70 km/h

  • 75 km/h

  • 72 km/h

  • 68 km/h


જો 't' સમયે કોઈ પથ્થરનું વેગમાન open square brackets open parentheses 0.5 space k g space m divided by s squared close parentheses t to the power of 2 space end exponent plus space open parentheses 3.0 space k g space m divided by s close parentheses close square brackets i with hat on top space plus space open square brackets 1.5 space k g space m divided by s squared close square brackets t space j with hat on top space space right square bracket હોય, તો તેના પર લાગતું બળ કેટલું હોય ?

  • open parentheses t space i with hat on top space plus space 1.5 space j with hat on top close parentheses space N
  • open parentheses 0.5 t i with hat on top space plus space 1.5 j with hat on top close parentheses space N
  • open square brackets open parentheses 0.5 t space plus space 3 close parentheses i with hat on top space plus space 1.5 space j with hat on top close square brackets space N
  • open parentheses 0.5 space i with hat on top space plus space 1.5 j with hat on top close parentheses space N

ધારો કે તમારું દ્રવ્યમાન 50 kg છે. તમારે કેટલી ઝડપથી દોડવું પડે કે જેથી તમારું રેખીય વેગમાન 20 km/h ની ઝડપથી સીધા રસ્તા પર ગતિ કરતા 100 kg સાઇકલ સવાર જેટલું થાય ? 

  • 40m/s

  • 11.11 m/s

  • 20 km/h

  • 10 km/h


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2 kg નું એક પક્ષી open parentheses 2 space i with hat on top space plus space 4 space j with hat on top close parentheses m/s ના અચળ વેગથી તથા 3 kg નું બીજું પક્ષી  open parentheses 2 space i with hat on top space plus space 6 space j with hat on top close parentheses m/s થી ઊડતાં હોય, તો બંને પક્ષી વડે બનતાં તંત્રના દ્રવ્યમાન-કેન્દ્રનો વેગ...... m/s હોય ?

  • open parentheses 2 space i with hat on top space plus space 5.2 space j with hat on top close parentheses
  • 2 space i with hat on top space plus space 2 space j with hat on top
  • 2 space i with hat on top space minus space 2 space j with hat on top
  • 10 space i with hat on top space plus space 10 space j with hat on top

B.

2 space i with hat on top space plus space 2 space j with hat on top

Tips: -

stack v subscript c m end subscript with rightwards arrow on top equals space fraction numerator m subscript 1 space stack v subscript 1 with rightwards arrow on top space plus space m subscript 2 space stack v subscript 2 with rightwards arrow on top over denominator m subscript 1 space plus space m subscript 2 end fraction space space space

       equals space fraction numerator open parentheses 2 close parentheses space open parentheses 2 space i with hat on top space minus space 4 space j with hat on top close parentheses space plus space open parentheses 3 close parentheses space open parentheses 2 space i with hat on top space plus space 6 space j with hat on top close parentheses over denominator 2 space plus space 3 end fraction

equals space fraction numerator 10 space i with hat on top space plus space 10 space j with hat on top over denominator 5 end fraction

equals space 2 space i with hat on top space plus space 2 space j with hat on top space space m divided by s

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0.100 gનું એક પીંછું  open parentheses negative 0.05 space j with hat on top close parentheses space m divided by s ના વેગથી નીચે પડે છે, નીચેથી તેના પર ફુંક મારતાં તેનો વેગ  open parentheses 0.20 space i with hat on top space plus space 0.15 space j with hat on top close parentheses space m divided by s થાય છે, તો તેના વેગમાનમાં થતો ફેરફાર.......... kg m/s  હશે.

  • 2 cross times 10 to the power of negative 2 end exponent space i with hat on top space plus space 2 cross times 10 to the power of negative 2 end exponent space j with hat on top
  • 2 cross times 10 to the power of negative 5 end exponent space i with hat on top space plus space 2 cross times 10 to the power of negative 5 end exponent space j with hat on top
  • 2 cross times 10 to the power of negative 2 end exponent space i with hat on top space plus space 1 cross times 10 to the power of negative 2 end exponent space j with hat on top
  • 2 cross times 10 to the power of negative 2 end exponent space i with hat on top space minus space 2 cross times 10 to the power of negative 2 space end exponent space j with hat on top

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