Trigonometry: Wanting someone to check my answer for Statics

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
3 replies · 2K views
blixel
Messages
52
Reaction score
1

Homework Statement


A building is 400 ft tall and has suffered damage from a recent earthquake. If a surveyor is stationed 150 ft away, sets a zero angle on the bottom corner of the building, and turns the angle shown to the top of the building; what is the angle at which the building is leaning with respect to vertical?

media2F5532F55321e7f-7f4c-4caa-802b-a8355fd584002Fimage_zpsxhvof20n.jpg


Homework Equations


I feel like I know what to do, but would like confirmation from the forum please.

The Attempt at a Solution


sin(70)/400 = sinC/150
sinC=[150*sin(70)]/400
C=arcsin([150*sin(70)]/400)~=20.6332
180-70-20.6332=89.3668

Therefore, Beta = 89.3668
 

Attachments

  • media2F5532F55321e7f-7f4c-4caa-802b-a8355fd584002Fimage_zpsxhvof20n.jpg
    media2F5532F55321e7f-7f4c-4caa-802b-a8355fd584002Fimage_zpsxhvof20n.jpg
    5.8 KB · Views: 353
Physics news on Phys.org
Seems correct to me. You use sine law to determine sinC and therefore C (provided that ##C<90##), and then knowing C and the angle of 70 degrees can determine the other angle of the triangle.

Just to add something if angle beta was smaller or the building height was not so big, angle C might have been >90 degrees.
 
  • Like
Likes   Reactions: blixel
gneill said:
Your work looks fine to me :smile:

Thanks for checking it over. The work felt right, but the image suggests a steeper angle, so I wasn't confident.