ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: stephanieteddy on August 23, 2012, 07:41:04 pm
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I am dying with the Kinematics and Dynamics chapters. My non-physics background is biting me in the bum and it hurts!
Can someone please please help me with the following question from Essential Maths 13A
I have no idea why the solutions do what they do.
Q 18 The angles between the forces of magnitude 8 N, 10 N and P N are, respectively, 60◦ and
90◦. The resultant acts along the 10 N force. Find P.
Solutions are: || 10 N: 10 + 8 cos 60° = 14 N
⊥ 10 N: 8 sin 60° – P
∴8 sin 60° – P = 0
∴P = 8 sin 60°
= 4 3 N
≈ 6.93 N
But whyyyyy :(
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Please help me
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I am dying with the Kinematics and Dynamics chapters. My non-physics background is biting me in the bum and it hurts!
Can someone please please help me with the following question from Essential Maths 13A
I have no idea why the solutions do what they do.
Q 18 The angles between the forces of magnitude 8 N, 10 N and P N are, respectively, 60◦ and
90◦. The resultant acts along the 10 N force. Find P.
Solutions are: || 10 N: 10 + 8 cos 60° = 14 N
⊥ 10 N: 8 sin 60° – P
∴8 sin 60° – P = 0
∴P = 8 sin 60°
= 4 3 N
≈ 6.93 N
But whyyyyy :(
why is the solution so long?
I just do 8/sin90=P/sin60 => P=8sin(60)=6.93N
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I think for that question it wanted you to use resolving forces? [like it actually says "use resolving forces for the following questions"]
IF IT DIDN'T, then just use lami's theorem (as jenny did)