# Solving Car Accident Problem: Jeep Speeding?

• jared13
In summary, a 1,600kg Jeep Cherokee and a 900kg Chevy convertible were involved in an accident on a dry road surface. The coefficient of sliding (kinetic friction) between the tires and the road was measured to be 0.45. The jeep left skid marks 23m long and the two vehicles were locked together for an additional 13m as they slid through a traffic light. The speed limit on that section of road was 45mph. Using the equations of motion and the conservation of energy, it can be determined whether the jeep was speeding before hitting its brakes.
jared13

## Homework Statement

Fresh from CSI training, you are sent to the scene of an accident. A 1,600kg Jeep Cherokee is locked in a crumpled pile of metal with what used to be a 900kg Chevy convertible. A witness tells you that the convertible was waiting at the light when the Jeep had hit its brakes and slid into the convertible, whereupon the convertible was crushed and the Jeep and convertible slid locked together until they came to rest. The witness also tells you that that at the time of the accident, the road surface was dry, just as it is when you arrive. After making some measurements, you determine that the coefficient of sliding (kinetic friction) beween the vehicle tires and the dry roadsurface is about .45. You also measure skid marks 23m in length on the road behind where the convertible was hit, and another 13m of skidmarks clearly form the jeep and convertible as they slid through the traffic light locked together. You check the road signs and see that the speed limit on that section of road is 45mph. Was the jeep speeding before it hit its brakes? (If so by how much?)

## Homework Equations

F=ma
x=x0+v0xt+1/2axt^2
v=v0x+axt
v^2x=v0x^2+2axx

## The Attempt at a Solution

Please help me I really don't know where to begin. If I had to take a guess I would say the coefficent of friction and the length of the skid marks has something to do with being able to judge how fast the car was going, but I do not not how they are linked.

Conservation of energy.
At the start you have kinetic energy of the jeep.
All this is converted into friction (if you assume the bang lost no energy!)

Remember energy is force * distance,
How o you work out frictional force?

As a scientist, my first step would be to gather all the necessary data and information. From the given information, we know the mass of the vehicles, the coefficient of sliding friction, and the length of the skid marks. We also know that the road surface was dry and the speed limit in that area is 45 mph.

Next, I would use the equations of motion to calculate the initial velocity of the Jeep before it hit its brakes. We can use the equation v^2 = v0^2 + 2ax to solve for v0, where v is the final velocity, v0 is the initial velocity, a is the acceleration (which in this case is due to friction), and x is the distance traveled (in this case, the length of the skid marks).

Plugging in the values, we get v0 = √(2ax) = √(2*0.45*23) = 6.32 m/s.

Now, we can convert this to mph by multiplying by 2.237 (1 m/s = 2.237 mph), giving us an initial velocity of approximately 14.15 mph.

Since the speed limit is 45 mph, we can conclude that the Jeep was not speeding before it hit its brakes. In fact, it was going significantly below the speed limit.

However, this does not necessarily mean that the Jeep was not at fault for the accident. There could have been other factors at play, such as the driver of the Jeep not paying attention or not braking in time. More investigation and analysis would be needed to determine the exact cause of the accident.

## 1. How common are car accidents involving speeding Jeeps?

According to the National Highway Traffic Safety Administration, speeding is a contributing factor in approximately one-third of all car accidents in the United States. While there is no specific data on the number of accidents involving speeding Jeeps, it is safe to say that they are a common occurrence.

## 2. What are the potential consequences of speeding in a Jeep?

The consequences of speeding in any vehicle can be severe, but they can be especially dangerous in a Jeep due to its high center of gravity and off-road capabilities. Speeding can increase the risk of losing control of the vehicle, rollovers, and collisions with other vehicles or objects.

## 3. How can I prevent car accidents caused by speeding in a Jeep?

The best way to prevent car accidents caused by speeding in a Jeep is to always obey the speed limit and drive at a safe and appropriate speed for the road and weather conditions. It is also important to regularly maintain your Jeep to ensure that all components are functioning properly.

## 4. What should I do if I am involved in a car accident caused by a speeding Jeep?

If you are involved in a car accident caused by a speeding Jeep, the first priority is to seek medical attention for anyone who is injured. Then, you should call the police and report the accident. It is also important to exchange insurance information with the other driver and document the scene with photos and witness statements.

## 5. Can a speeding Jeep be considered a defective product?

In some cases, a speeding Jeep can be considered a defective product if it was found to have a manufacturing or design defect that caused the accident. This may be grounds for a product liability lawsuit against the manufacturer. However, each case is unique, and it is best to consult with an experienced lawyer to determine the best course of action.

• Introductory Physics Homework Help
Replies
9
Views
3K
• Introductory Physics Homework Help
Replies
8
Views
7K
• Introductory Physics Homework Help
Replies
12
Views
5K
• Introductory Physics Homework Help
Replies
4
Views
2K
• Introductory Physics Homework Help
Replies
8
Views
2K
• Introductory Physics Homework Help
Replies
2
Views
2K
• Introductory Physics Homework Help
Replies
9
Views
3K
• Introductory Physics Homework Help
Replies
5
Views
1K
• Introductory Physics Homework Help
Replies
4
Views
3K
• Introductory Physics Homework Help
Replies
5
Views
2K