Two cars collide at an intersection. Car A, with a mass of 1900 kg , is going fr

Question

Two cars collide at an intersection. Car A, with a mass of 1900 kg , is going from west to east, while car B , of mass 1500 kg , is going from north to south at 12 m/s . As a result of this collision, the two cars become enmeshed and move as one afterwards. In your role as an expert witness, you inspect the scene and determine that, after the collision, the enmeshed cars moved at an angle of 55 south of east from the point of impact.

1. How fast were the enmeshed cars moving just after the collision?

2. How fast was car A going just before the collision?

Explanation / Answer

Apply conservation of momentum along west east axis

Ma*Va = (Ma+Mb)*V*cos(55o)

V=(1900*Va)/[(1900+1500)*cos(55o)]

= 0.974*Va

conservation of mometum along y axis ( north south axis)

Mb*Vb = (Ma+Mb)*V*sin(55o)

V=(1500*12)/[(1900+1500)*sin(55o)]

= 6.46 m/s

from the above two values

0.974*Va = 6.46

Va = 6.63 m/s

ANSWERS

(1)6.46 m/s.

(2) 6.63 m/s

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