Expert Witness Analysis: Speeding in Car Accident Case

Question:

Was the driver of car A exceeding the 55-mph speed limit before applying his brakes?

Answer:

To prove to the court that the driver of car A was exceeding the 55-mph speed limit before applying his brakes, we can analyze the physics of the collision and the subsequent skidding of both cars.

Physics Analysis of the Collision:

First, let’s calculate the initial velocities of car A and car B before the collision. We can use the conservation of momentum:

Initial momentum of car A = Final momentum of car A + Final momentum of car B

1500 kg × (initial velocity of car A) = 1500 kg × (final velocity of car A) + 1100 kg × 0

Next, we need to calculate the kinetic energy of car A before applying the brakes:

Kinetic energy = 0.5 × (mass of car A) × (initial velocity of car A)^2

If the calculated kinetic energy is greater than the energy required to overcome the frictional force and bring car A to a stop, we can conclude that car A was traveling at a speed higher than the speed limit. The frictional force can be calculated using the coefficient of kinetic friction and the weight of car A.