Phsyics problem. I must find distance in Kilometers.

  • Thread starter afcwestwarrior
  • Start date
  • Tags
    Phsyics
In summary, the conversation is about estimating the distance to the famous Gateway-to-the-west arch in St. Louis, Missouri. The monument has a height of 192m and the person estimates their line of sight to be at a 2.0 degree angle from the horizontal. They use the definition of trigonometric functions to solve for the distance and convert it to kilometers, with a final answer of approximately 5.498km. There is also a brief discussion about unit conversions and the correct abbreviation for meters and miles.
  • #1
afcwestwarrior
457
0

Homework Statement


You are driving into St.Louis Missouri, and in the distance you see the famous Gateway-to-the-west arch. This monument rises to a height of 192 m. You estimate your line of sight with the top of the arch to be 2.0 degrees above the horizontal. Approximately how far (In Kilometers) are you from the base of the arch.


Height= 192 m
Angle= 2.0 degrees

2. Homework Equations [/b
Definition of Cos, Sin, and Tan or the inverse trigonometric functions


I have no clue on what I should do.
This is what I did.
H adjacent= 192/tan(2.0)= 5498m and then I converted it to KM and I got 8848 km. This answer is way off, and I know I'm doing something wrong.
 
Physics news on Phys.org
  • #2
You did the equation right.

tanØ = y/x

x = height/tan2

x = 5498m

How many meters are in a kilometer?
 
  • #3
You were doing great until you tried to convert the units. What strange conversion formula are you using? m -> km just involves dividing by 1000.
 
  • #4
1,000 meters equal 1 kilometer, oh no wonder I had a reference sheet that said 1 KM equals .6214 Meters. Ok so the answer is 5.498. Thank you for helping me out.
 
Last edited:
  • #5
km=0.6214 MILE. I wouldn't use the same abbreviation for meter and mile!
 
  • #6
Oh lol no wonder. In my conversion factor reference it just had m as the symbol, so it confused me.
 
  • #7
Remember, it is a KILOmeter. Kilo means 10^3, so 1000meter. ;)
 

1. How do I convert units in physics problems?

In order to convert distance in kilometers, you can use the conversion factor 1 kilometer = 1000 meters. This means that to convert a distance in kilometers to meters, you would multiply the distance in kilometers by 1000. For example, if you have a distance of 5 kilometers, you would multiply 5 by 1000 to get 5000 meters.

2. How do I use the formula for distance to solve a physics problem?

The formula for distance is distance = speed x time. In order to solve a physics problem involving distance, you would need to know two of these variables and use algebra to solve for the third. For example, if you know the speed is 50 km/h and the time is 2 hours, you can plug these values into the formula to find the distance (distance = 50 km/h x 2 h = 100 km).

3. What is the difference between distance and displacement?

Distance is the total amount of ground covered, while displacement is the straight-line distance between the starting and ending points. For example, if you walk 5 kilometers in a straight line, your displacement would be 5 kilometers. But if you walk 5 kilometers in a zigzag pattern, your distance would be greater than 5 kilometers, but your displacement would still be 5 kilometers.

4. What is the SI unit for distance?

The SI unit for distance is meters (m). However, in some cases, it may be more convenient to use larger units such as kilometers (km) or centimeters (cm) depending on the scale of the problem.

5. How do I find the distance traveled in a physics problem with changing speed?

In order to find the distance traveled in a problem with changing speed, you would need to use the formula for average speed: average speed = total distance / total time. This formula takes into account the different speeds at different points during the journey. Simply plug in the values given in the problem to find the distance traveled.

Similar threads

  • Introductory Physics Homework Help
Replies
9
Views
3K
Replies
5
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
1K
Replies
17
Views
2K
  • Introductory Physics Homework Help
Replies
11
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
747
  • Introductory Physics Homework Help
Replies
6
Views
5K
  • Introductory Physics Homework Help
Replies
6
Views
3K
Back
Top