Calculating Maximum Acceleration in Runaway Escape Ramp

In summary, the conversation discusses the calculation of acceleration applied to a truck in a runaway escape ramp. It is determined that knowing either the time or distance would be necessary to calculate the acceleration, and that the angle of the incline and the condition of the ramp play a significant role. It is also noted that the acceleration may vary depending on the weight and speed of the truck. Ultimately, it is suggested that the best way to obtain accurate information would be to conduct experiments with different trucks and ramps.
  • #1
skipo947
3
0
Is there a way to calculate the acceleration (in g's) applied to a truck as it is stopped in a runaway escape ramp? Do I need to know how long it takes or how far it goes in the ramp to calculate the acceleration?
 
Physics news on Phys.org
  • #2
If you knew the elapsed time until the truck stops (T), you could calculate the average acceleration by dividing the truck's initial velocity (V0) into T. It's important to realize this quotient gives only the average acceleration; if you want the actual motion you'd need extra data about the escape track (slope, surface, wind and many more things)
 
  • #3
v^2=u^2 + 2as

v=final velocity
u= intial velocity
a= acceleration
s= change in distance

or
v=u+at
 
Last edited:
  • #4
skipo947 said:
Do I need to know how long it takes or how far it goes in the ramp to calculate the acceleration?

You need to know one or the other.
 
  • #5
Thank you all for your replies. I thought I was going to need either the time or distance.
 
  • #6
I think all you need is the angle of the incline. If the angle formed by the ramp and the horizontal is [tex]\theta[/tex], then the deceleration component alone the truck's trajectory would then just be [tex]g \sin \theta[/tex], where g is the familiar 9.8 m/sec^2 gravitational acceleration of the Earth.

But if the truck's brakes work, then the deceleration would be greater, but at least you could get a reasonable upper bound.
 
  • #7
We must decide whether we're speaking of an idealized truck (and road) or a real one. Escape tracks are inclined but they're also covered with a layer of small rocks. These rocks play an important role; the tyres virtually "sink" in the bed of small rocks, thus expending a great amount of energy. This accounts for most of the braking action.
 
  • #8
Thanks Gordianus. Ultimately, I am trying to figure out if there is a way to calculate the maximum acceleration that an escape ramp will apply to any truck that enters it - real world truck and ramp. My physics/math knowledge is a little limited - I understand the formulae, it's picking the right ones to apply that is hampering me.

My gut feeling is that it is not possible to calculate a maximum acceleration that a ramp will impart without knowing EVERYTHING about both the ramp and the truck that is using it.

It also seems that the acceleration on two different trucks using the same ramp will be dependent on their speeds and weights. Wouldn't a 50k lb truck be stopped much quicker than an 80k lb one at the same speed, in the same ramp?

I am beginning to believe that the only way to solve the question is to instrument a bunch of trucks with different weights and drive them into several different escape ramps at various speeds.

Thanks again for all your help, Everyone.
S
"Not everything that can be counted counts, and not everything that counts can be counted." ------Albert Einstein
 

1. What is acceleration?

Acceleration is the rate at which an object's velocity changes over time. It is a vector quantity, meaning it has both magnitude and direction. If an object's acceleration is positive, it is speeding up, and if it is negative, it is slowing down.

2. How do you calculate acceleration?

Acceleration can be calculated by dividing the change in an object's velocity by the change in time. This is represented by the formula a = (vf - vi) / t, where a is acceleration, vf is final velocity, vi is initial velocity, and t is time.

3. What is deceleration?

Deceleration is a type of acceleration that occurs when an object's velocity decreases. It is often referred to as negative acceleration and can be caused by forces such as friction or air resistance.

4. How is acceleration related to force?

Newton's Second Law of Motion states that acceleration is directly proportional to the net force acting on an object and inversely proportional to its mass. This means that the greater the force applied to an object, the greater its acceleration will be. Similarly, the more massive an object is, the less it will accelerate for a given force.

5. Can acceleration be negative?

Yes, acceleration can be negative. This occurs when an object's velocity and acceleration are in opposite directions. For example, if a car is traveling east but slowing down, its acceleration would be in the westward direction, making it negative.

Similar threads

Replies
9
Views
1K
  • Mechanics
Replies
5
Views
2K
  • Mechanics
Replies
4
Views
827
  • Mechanics
Replies
3
Views
522
  • Mechanics
Replies
5
Views
2K
Replies
4
Views
2K
Replies
7
Views
2K
  • General Engineering
2
Replies
68
Views
5K
Replies
1
Views
959
  • Introductory Physics Homework Help
Replies
6
Views
626
Back
Top