Register to reply 
Physics Problem. I must find time. 
Share this thread: 
#1
Aug3007, 09:52 PM

P: 457

1. The problem statement, all variables and given/known data
You are on a train that is traveling 3.0 m/s (to the left direction) along a level straight track. very near and parallel to the track is a wall that slopes upward at a 12 degree angle with the horizontal. As you face the windoes (.90 m high), (2.0 m wide) in your compartment, the train is moving to the left. The top edge of the wall 1st appears at window corner A and eventually disappears at window corner A and eventually disappears at window corner B. How much time passes between appearance and disappearance of the upper edge of the wall. 2. Relevant equations Time= distance/average speed 3. The attempt at a solution I multiplied .90 and 2.0 and I got .18m and then I divided it by 3.0 and I got .06 s. This is way off. What do I need to do. 


#2
Aug3107, 09:20 AM

HW Helper
P: 4,124

Why did you multiply the lengths?
You need to find the horizontal distance travelled... draw a picture... how do the window and wall look right as the wall appears... and draw another picture right when the wall leaves... What is the total horizontal distance? Hint: it is more than 2.0m. you'll need a little trig. Once you get the distance, divide by velocity to get time. 


#3
Aug3107, 09:35 AM

Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 39,353

?? Even your multiplication is wrong: if the window has width 2.0 m and height 0.9 m, then it has area 1.8 m^{2} but that has nothing to do with the problem.



Register to reply 
Related Discussions  
Physics motivated POVs in the time problem  General Discussion  11  
Physics Problem find displacement.  Introductory Physics Homework  3  
Physics Problem. I must find acceleration.  Introductory Physics Homework  6  
Physics Problem. I must find the horizontal distance x between the 2 baloons.  Introductory Physics Homework  2  
Physics: distance, rate, time problem  Introductory Physics Homework  4 