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4. A 1200 kg car traveling North at 20.0 m/s collides with a 1400 kg car traveling South at 22.0 m/s. The two
cars collide and entangle. What is the resulting velocity of the wreckage?

Respuesta :

Answer:-2.61 m/s

Explanation:

This problem can be solved by the Conservation of Momentum principle, which establishes that the initial momentum [tex]p_{o}[/tex] must be equal to the final momentum [tex]p_{f}[/tex]:

[tex]p_{o}=p_{f}[/tex] (1)

Where:

[tex]p_{o}=mV_{o}+MU_{o}[/tex] (2)

[tex]p_{f}=(m+M)V_{f}[/tex] (3)

[tex]m=1200 kg[/tex] is the mass of the first car

[tex]V_{o}=20 m/s[/tex] is the velocity of the first car, to the North

[tex]M=1400 kg[/tex] is the mass of the second car

[tex]U_{o}=-22 m/s[/tex] is the mass of the second car, to the South

[tex]V_{f}[/tex] is the final velocity of both cars after the collision

[tex]mV_{o}+MU_{o}=(m+M)V_{f}[/tex] (4)

Isolating [tex]V_{f}[/tex]:

[tex]V_{f}=\frac{mV_{o}+MU_{o}}{m+M}[/tex] (5)

[tex]V_{f}=\frac{(1200 kg)(20 m/s)+(1400 kg)(-22 m/s)}{1200 kg+1400 kg}[/tex] (6)

Finally:

[tex]V_{f}=-2.61 m/s[/tex] (7) This is the resulting velocity of the wreckage, to the south