8.29 Two cars collide at an intersection. Car A , with a mass of 2000 kg , is go

Question

8.29

Two cars collide at an intersection. Car A, with a mass of 2000 kg , is going from west to east, while car B, of mass 1300 kg , is going from north to south at 17.0 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 65.0 south of east from the point of impact.

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

ANSWER: V = __________ m/s

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

ANSWER: Va = __________ m/s

Explanation / Answer

As this is a inelastic collision. So momentum is conserved.
Since this is a 2-D collision we need to take momentum in both x and y directions
Car A
m1= 2000 Kg
u1=?

Car B
m2=1300Kg
u2=17m/s

After collission
Mass M = m1+m2=3300Kg
velocity = V

Conservation of Momentum in y-direction
m2u2 = MVsin65
1300 * 17 = 3300 V * sin65
V= 7.38 m/s .........enmeshed cars moving after collision

Conservation of Momentum in x-direction
m1u1 = MVcos60
2000 u1 = 3300*7.38*cos65
u1 = 5.14 m/s .........velocity of Car A before collision

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