Stopping Distance of a Locomotive with Failed Engine and Brakes

In summary, the problem involves a 49,000 kg locomotive traveling at 11 m/s with both its engine and brakes failed. The goal is to determine the stopping distance of the locomotive. The solution involves drawing a force diagram and using the equations F = ma, Fr = µr x n, Max = F1 - F2, and May = F1 - F2. However, to fully solve the problem, the coefficients of friction are needed. Without them, it is difficult to calculate the deceleration and ultimately the stopping distance.
  • #1
Phoenixtears
83
0

Homework Statement



a. A 49,000 kg locomotive is traveling at 11 m/s when its engine and brakes both fail. How far will the locomotive roll before it comes to a stop?
_____m

b. Determine the stopping distance if the locomotive had the same initial velocity but was "low on diesel" so its mass was only 35,000 kg.
______m

Homework Equations



Fr = µr x n
F = ma
Max = F1 - F2
May = F1 - F2


The Attempt at a Solution



To start off I drew a force diagram which showed thre forces; normal force going up, weight going down, and friction going in the opposite direction of the car. I found weight by multiplying the mass by 9.8, which ended up being 408200. I know that this must also be the amount for the normal force. But, now I'm at a standstill. I don't think the coefficients have anything to do with the problem but I'm starting to second guess myself. Am I able to use the mass and weight to figure out the decceleration of the car so that I will be able to use the velocity to find the distance? Thank you in advance!
 
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  • #2
It looks to me like you need the coefficients of friction.
 
  • #3
Mattowander said:
It looks to me like you need the coefficients of friction.

That seems logical, but there is no way to get them with just the mass and velocity. Velocity seems pretty pointless, especially at this stage in the problem, and all that mass can give us is weight, but using 9.8 as the acceleration.

How else can I approach the problem?
 

FAQ: Stopping Distance of a Locomotive with Failed Engine and Brakes

What is car rolling?

Car rolling is the movement of a car without any external force or power, caused by the force of gravity. It occurs when a car is on an inclined surface or when it is in neutral gear and on a flat surface.

How does friction affect car rolling?

Friction is the force that opposes motion between two surfaces in contact. In the case of car rolling, friction plays a crucial role in slowing down the car's movement and eventually stopping it. The amount of friction between the car's tires and the ground will determine how quickly the car will come to a stop.

What factors affect the amount of friction between the car's tires and the ground?

The amount of friction between the car's tires and the ground is affected by several factors, including the type of tire, the type of surface the car is on, the weight of the car, and the condition of the tires. For example, a car with worn-out tires will have less friction and will roll further than a car with new tires on the same surface.

How can friction be reduced in car rolling?

One way to reduce friction in car rolling is by using lubricants, such as oil or grease, on the moving parts of the car, such as the wheels and axles. Another way is by using smoother and more aerodynamic tires, which will have less contact with the ground and therefore less friction.

How does car rolling relate to energy conservation?

Car rolling is an example of potential energy being converted into kinetic energy. As the car rolls down an inclined surface, its potential energy decreases, and its kinetic energy increases. This conversion follows the law of conservation of energy, which states that energy cannot be created or destroyed, only transformed from one form to another.

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