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The force 'F' acting on a particle of mass 'm' is indicated by the force - time graph shown below. The change in momentum of the particle over the time interval from zero to 8 s is:

 

  • Option 1)

    24 Ns

  • Option 2)

    20 Ns

  • Option 3)

    12 Ns

  • Option 4)

    6 Ns

 

Answers (1)

best_answer

As we learnt in

Impulse -

vec{I}=int_{t_{1}}^{t_{2}}vec{F}cdot dt

astleft [ MLT^{-1} 
ight ]

- wherein

 

 

 

Area of F-t graph gives change in momentum

For 0 to 2 sec

\Delta P_{1}=\frac{1}{2}\times2\times 6=6kg-m/s

For 2-4

\Delta P_{2}=2\times(-3)=-6kg-m/s

\Delta P_{3}=4\times 3=12kg-m/s

Total change in momentum 0 to 8 sec

\Delta P_{net}=\Delta\: P_{1}+\Delta\: P_{2}+\Delta\: P_{3}

=6-6+12=12N-s

Correct option is 3.


Option 1)

24 Ns

Incorrect

Option 2)

20 Ns

Incorrect

Option 3)

12 Ns

Correct

Option 4)

6 Ns

Incorrect

Posted by

Plabita

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