Calculating Distance for a Train on a 1% Grade

In summary, the question asks for the horizontal distance a 60,000kg train will travel before its initial speed of 12 m/s is reduced to 9 m/s while being pulled up a 1 percent grade. The friction force opposing the motion of the train is 4,000N. The correct answer is 191.2 m, but the given calculation method results in 472.5 m. To solve this problem, the kinematic equation ##\Delta x=\dfrac{v_f^2-v_i^2}{2a}## can be used, where the acceleration is not given and needs to be calculated. Additional information and assumptions may be needed to accurately solve the problem.
  • #1
A_Sushi
Can anyone help with the following question, please?
1.
A 60,000kg train is being pulled up a 1 percent grade (it rises 1m for each horizontal 100m). The friction force opposing the motion of the train is 4,000N. Initial speed of the train is 12 m/s. Through what horizontal distance will the train move before its speed is reduced to 9m/s?
3.
The answer suppose to be 191.2 m. I got 472.5 m as follows:
Fd=m*(v2-v2)/(2*distance)
4 000 = (60 000*(92-122)) / (2*distance) = 472.5 m
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
Use the kinematic equation:

##\Delta x=\dfrac{v_f^2-v_i^2}{2a}##

You are given the initial and final velocities...what is the acceleration? How does ##\Delta x## relate to the horizontal distance?
 
  • #3
@A_Sushi Please do not delete our template, but use it instead. It is important for many reasons. Also we request you to show us some effort on your own, to see how we could help you best. Different people might have different difficulties. Thank you.
 
  • Like
Likes MarkFL
  • #4
MarkFL said:
Use the kinematic equation:

##\Delta x=\dfrac{v_f^2-v_i^2}{2a}##

You are given the initial and final velocities...what is the acceleration? How does ##\Delta x## relate to the horizontal distance?
The acceleration is not given. I do not know how to calculate the acceleration
 
  • #5
A_Sushi said:
how to calculate the acceleration
Even though it says the train is being pulled up, I think you have to assume there is no engine attached, it is just coasting.
What are the forces on the train? What equation can you write relating those to acceleration?
 

1. How is distance calculated for a train on a 1% grade?

The distance for a train on a 1% grade is calculated by multiplying the gradient (1%) by the length of the track. This will give you the vertical distance that the train will travel for every 100 units of horizontal distance.

2. What is a 1% grade?

A 1% grade, also known as a 1% slope, is a measure of the change in elevation over a given distance. It means that for every 100 units of horizontal distance, there is a 1 unit change in elevation.

3. How does the 1% grade affect the train's speed and distance traveled?

A 1% grade will cause the train to travel at a slightly slower speed and cover a greater distance compared to traveling on a flat surface. This is because the train has to work against gravity to climb the incline, resulting in a decrease in speed and an increase in distance traveled.

4. Is the 1% grade the same as a 1 degree incline?

No, a 1% grade is not the same as a 1 degree incline. A 1% grade means a 1% change in elevation for every 100 units of horizontal distance, while a 1 degree incline means a 1 unit change in elevation for every 57.3 units of horizontal distance.

5. How does the length of the train affect the distance traveled on a 1% grade?

The length of the train does not have a significant impact on the distance traveled on a 1% grade. The distance traveled will still be calculated using the same formula of multiplying the gradient by the length of the track. However, a longer train may experience more resistance and require more power to climb the incline, resulting in a slightly slower speed and a greater distance traveled.

Similar threads

  • Introductory Physics Homework Help
Replies
11
Views
784
  • Introductory Physics Homework Help
Replies
1
Views
3K
  • Introductory Physics Homework Help
2
Replies
39
Views
6K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
5
Views
2K
  • Introductory Physics Homework Help
Replies
23
Views
4K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
4K
  • Introductory Physics Homework Help
Replies
1
Views
2K
Back
Top