Asked by yasmin
The base of the roof, ππ΄π΅πΆ, is rectangular and horizontal with ππ΄ = πΆπ΅ = 14 π and ππΆ = π΄π΅ = 8 π. The top of the roof π·πΈ is 5 π above the base and DE = 6m. The sloping edges ππ·,πΆπ·,π΄πΈ and π΅πΈ are all equal in length.
Unit vector i and j are parallel to OA and OC respectively and the unit vectors k is vertically upwards.
(i) Express the vector ππ·ββββββ in terms of i , j and k, and find its magnitude (4 marks)
(ii) Use a scalar product to find angle π·ππ΅. (5 marks)
Unit vector i and j are parallel to OA and OC respectively and the unit vectors k is vertically upwards.
(i) Express the vector ππ·ββββββ in terms of i , j and k, and find its magnitude (4 marks)
(ii) Use a scalar product to find angle π·ππ΅. (5 marks)
Answers
Answered by
oobleck
D is 4m in from AC, so
OD = 4i+4j+4k
OB = 14i+8j
If ΞΈ = β‘DOB, then
OBβ’OD = |OB| * |OD| cosΞΈ
I assume you know how to find the dot product and magnitudes
OD = 4i+4j+4k
OB = 14i+8j
If ΞΈ = β‘DOB, then
OBβ’OD = |OB| * |OD| cosΞΈ
I assume you know how to find the dot product and magnitudes
There are no AI answers yet. The ability to request AI answers is coming soon!
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.