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A 225 kg red bumper car is moving at 3.0 m/s. It hits a stationary 180 kg blue bumper car. The red and blue bumper cars combine and hit a stationary green bumper car of mass 150 kg. The red, blue, and green bumper cars all combine.
A. 0.93 m/s
B 1.2 m/s
C 1.7 m/s
D 2.7 m/s

Respuesta :

i think the answer for the question above its            b 1.2

Answer:

B. 1.2m/s

Explanation:

as per the law of conservation of momentum,

initial momentum= final momentum

considering collision 1 : Mr * Vr + ( Mb * Vb) = ( Mr + Mb ) Vrb

where Vrb is the final velocity after 1st collision with which red and blue car moves.

therefore,  225* 3 + 0 = ( 225 + 180 ) Vrb

Vrb = 675/405

       = 1.67m/s

now collision 2 : ( Mr+ Mb) Vrb + MgVg= ( Mr+ Mg+ Mb ) V'

where V' is the total speed

675 + 0 = 555V'

V' = 675/555

   = 1.2 m/s

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