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The value of 50C4 + not stretchy sum subscript r equals 1 end subscript superscript 6 end superscript 56 minus r C subscript 3 end subscriptis -

  1. 55C4    
  2. 55C3    
  3. 56C3    
  4. 56C4    

The correct answer is: 56C4

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Initial momentum stack P with rightwards arrow on top subscript 1 end subscript equals m v sin invisible function application theta stack i with hat on top plus m v cos invisible function application theta blank stack j with hat on top
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A mass of 100 blank g strikes the wall with speed 5 blank m divided by s at an angle as shown in figure and it rebounds with the same speed. If the contact time is 2 cross times 10 to the power of negative 3 end exponent s e c, what is the force applied on the mass by the wall

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Force = Rate of change of momentum
Initial momentum stack P with rightwards arrow on top subscript 1 end subscript equals m v sin invisible function application theta stack i with hat on top plus m v cos invisible function application theta blank stack j with hat on top
Final momentum stack P with rightwards arrow on top subscript 2 end subscript equals negative m v sin invisible function application theta stack i with hat on top plus m v cos invisible function application theta blank stack j with hat on top
therefore stack F with rightwards arrow on top equals fraction numerator increment stack P with rightwards arrow on top over denominator increment t end fraction equals fraction numerator negative 2 m v sin invisible function application theta over denominator 2 cross times 10 to the power of negative 3 end exponent end fraction
Substituting m equals 0.1 blank k g comma blank v equals 5 blank m divided by s comma blank theta equals 60 degree
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