The discussion revolves around the resultant of two forces, specifically focusing on the application of the law of cosines in vector addition. Participants are analyzing a scenario involving two vectors, P and Q, and their relationship through algebraic expressions.
The conversation is ongoing, with participants providing insights and corrections to previous posts. Some have pointed out inconsistencies in the calculations, while others are attempting to clarify the relationships between the variables involved. There is no explicit consensus on the validity of the problem, but productive questioning is occurring.
Participants are addressing potential errors in the problem's numerical values and the implications of these errors on the solvability of the question. There is a recognition that the original poster may have made a mistake in their setup, which could affect the overall discussion.
You have a sign error. Do a Google search for law of cosines.GiriBang said:Root(P²+Q²+2PQcosø)
OP has worked out thatSteve4Physics said:You have worked out that P² + Q² =100 and 2PQ = 69
The question is insoluble - well spotted. It might be a mistake in the question but it could be deliberate.kuruman said:OP has worked out that
P² + Q² =100 and PQ = 69.
I agree that P² + Q² =100 and that PQ = 69 which makes 2PQ = 138. But if that were true, then P² + Q² - 2PQ = (P-Q)2 = 100 - 138 = -38. The square of a (real) number is never negative.
It looks like the numbers are bad.