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Unit 3

1. At an intersection a car collides at a right angle with a SUV. The car travelling east has a mass of 1985
kg and a velocity of 25 m/s and the SUV travelling north has a mass of 3050 kg and a velocity of 21
km/hr.
A) What vehicle has the greater momentum?
B) What is the rebound angle of the wreckage after impact?
C) What is the velocity of each vehicle after impact?
D) What is the change in momentum for each vehicle?
E) The impact lasts .072 s, what is the force applied by each vehicle at impact?
F) The wreckage comes to a rest after 2.25 s, how far did the car travel after impact?
G) The speed limit is 95 km/hr, was anybody speeding?
ce of 7910 N the impact lasts .0049 s.

User Akuma
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1 Answer

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Final answer:

The center-of-mass velocity of two colliding cars that stick together after the collision will not change because momentum is conserved. This is evident when calculating the combined momentum before the collision and knowing that they move as one unit without external horizontal forces after the collision.

Step-by-step explanation:

In the scenario where Car A has a mass of 2000 kg and approaches an intersection with a velocity of 38 m/s directed to the east, and Car B has a mass of 3500 kg and approaches the intersection with a velocity of 53 m/s directed 63° north of east, the two cars collide and stick together. The center-of-mass velocity will not change as a result of the collision because momentum is conserved in the absence of external forces.

To calculate the center-of-mass velocity before the collision:

  • Resolve the velocity of Car B into x and y components.
  • Calculate the momentum of both cars in the x and y directions.
  • Divide the total momentum by the total mass of the system to get the velocity components of the center of mass.

After the collision, the velocity of the center of mass will be the same since the cars stick together and move as one object, and there are no external forces involved in the horizontal plane.

User James Andresakis
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8.4k points