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  • Give answer! A bus is moving with a speed of 10ms-1on a straigth road. A scooterist wishes to overtake the bus in 100s. If the bus is at a distance of 1km from the scooterist, with what speed should the scooterist chase the bus?

A bus is moving with a speed of 10ms-1 on a straigth road. A scooterist wishes to overtake the bus in 100s. If the bus is at a distance of 1km from the scooterist, with what speed should the scooterist chase the bus?

  • Option 1)

    40ms-1

  • Option 2)

    25ms-1

  • Option 3)

    10ms-1

  • Option 4)

    20ms-1

 

Answers (1)

best_answer

Using

Case of Relative velocity. -

When A and B are moving along a straight line in the same direction.

underset{V_A}{ ightarrow} = Velocity of object A.

underset{V_B}{ ightarrow} = Velocity of object B.

Relative velocity  of A wr to B is

vec{V}_{AB}=vec{V}_{A}-vec{V}_{B}

vec{V}_{AB},vec{V}_{A},vec{V}_{B} All are in same direction.

vec{V}_{BA}=vec{V}_{B}-vec{V}_{A}

 

 

- wherein

a)   vec{V}_{AB}=vec{V}_{A}-vec{V}_{B}

        = (20 - 5) ms-1

        = 15 ms-1

b)    vec{V}_{BA}=vec{V}_{B}-vec{V}_{A}

         = (5 - 20) ms-1

         = - 15 ms-1

 

 

 Relative velocity of scooter with respect to bus, v = vS - vB 

v = \frac{1000}{100} = 10\ ms^{-1}\ \ \ \ v_{B} = 10\ ms^{-1}

\therefore v_{S}= v + v_{B} = 10+10 = 20\ ms^{-1}


Option 1)

40ms-1

This option is incorrect

Option 2)

25ms-1

This option is incorrect

Option 3)

10ms-1

This option is incorrect

Option 4)

20ms-1

This option is correct

Posted by

Aadil

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