Physics: Vectors and Homework Solution

  • Thread starter Thread starter sucksatphysic
  • Start date Start date
  • Tags Tags
    Physics Vectors
AI Thread Summary
The discussion centers on solving a physics homework problem involving vector analysis of an off-roader's trip. The first leg of the journey is 25 degrees west of north at 6.5 km/h for 15 minutes, followed by a due east leg at 12 km/h for 7.5 minutes. Participants clarify that the trip does not form a right triangle, despite the angles involved. The need to calculate distances for the first two legs is emphasized to determine the direction and speed for the final leg. Understanding the diagram and angles is crucial for solving the problem accurately.
sucksatphysic
Messages
4
Reaction score
0

Homework Statement



An off-roader explores the open desert in her Hummer. First she drives 25 deg west of north with a speed of 6.5 km/h for 15 mins, then due east with a speed of 12 km /h for 7.5 mins. She completes the final leg of her trip in 22 mins. What are the direction and speed of travel on the final leg? (assume her speed is constant on each leg, and that she returns to her starting point at the end of the final leg)

So I know how to do it, but i am having a bit of trouble trying to figure out the diagram...

can you tell me if it's a right angle triangle?
which angles do i use?

thanks =)
 
Physics news on Phys.org
sucksatphysic said:

Homework Statement



An off-roader explores the open desert in her Hummer. First she drives 25 deg west of north with a speed of 6.5 km/h for 15 mins, then due east with a speed of 12 km /h for 7.5 mins. She completes the final leg of her trip in 22 mins. What are the direction and speed of travel on the final leg? (assume her speed is constant on each leg, and that she returns to her starting point at the end of the final leg)

So I know how to do it, but i am having a bit of trouble trying to figure out the diagram...

can you tell me if it's a right angle triangle?
which angles do i use?

thanks =)

Well, the first vector goes 25* N of W. So, draw a straight line going up, representing north. Next, draw a diagonal line going to the west but having the same starting point as the line to the north. The angle you just made is the 25* N of W, so it's 25*. Finally, she goes due east, which is a straight horizontal line right. The angle that line makes with the north line is 90*. The north line is now also the final leg of her trip.

With I could draw a diagram myself to help you, but I can't, so I hoped I helped.
 
sucksatphysic said:
So I know how to do it, but i am having a bit of trouble trying to figure out the diagram...

can you tell me if it's a right angle triangle?
It is not necessarily a right triangle.

which angles do i use?
See pbdude's response.

Also, you'll need to figure out the distances traveled in each of the 1st two legs.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top