Analysis of Auto Accident: Speed Calculation and Collision Explanation

Auto Accident Analysis

You are called as an expert witness to analyze the following auto accident: Car B, of mass 2100 kg, was stopped at a red light when it was hit from behind by car A, of mass 1500 kg. The cars locked bumpers during the collision and slid to a stop. Measurements of the skid marks left by the tires showed them to be 7.30 m long, and inspection of the tire tread revealed that the coefficient of kinetic friction between the tires and the road was 0.65.

Calculating Car A's Speed

  1. (a) What was the speed of car A just before the collision?
    2. The speed of car A just before the collision can be calculated using the law of conservation of momentum and the work-energy principle. The speed is determined to be 51.58 mph.
  2. (b) Was car A speeding with a speed limit of 35 mph, and if so, by how many miles per hour?
    3. With the given speed limit of 35 miles per hour, car A was exceeding the speed limit by 16.58 mph.

Explanation of Collision

Collision is defined as the event when two objects strike each other from either direction. During a collision, the speed of colliding objects may vary according to the direction of the approach. The key data provided for the analysis:
  • The mass of car A: 1500 kg
  • The mass of car B: 2100 kg
  • The length of the skid mark: 7.30 m
  • The coefficient of kinetic friction between tires and road: 0.65
To calculate the speed of car A just before the collision, the law of conservation of momentum and work-energy principle were applied. The speed was determined to be 51.58 mph. Considering the speed limit of 35 mph, car A was exceeding the limit by 16.58 mph. This analysis helps in understanding the dynamics of the auto accident and the factors contributing to the collision.

What is collision?

The event when two objects strike each other from either direction, then such event is known as a collision. During the collision, the speed of colliding objects may vary according to the direction of the approach.
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