thanks for everyone helping me ;) i am really greatful ,and the explations are makiing understand more thank you ...i need help in this homework too ,and i need answers for all please..there is another part continued.

regards

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- May 23rd 2007, 05:50 AMcarlasaderA level Maths part 05
thanks for everyone helping me ;) i am really greatful ,and the explations are makiing understand more thank you ...i need help in this homework too ,and i need answers for all please..there is another part continued.

regards - May 24th 2007, 04:04 AMCaptainBlack

http://www.mathhelpforum.com/math-he...untitled-1.jpg

1. Vector sum of forces:

$\displaystyle

\bold{V} = (2\bold{i} + \bold{j}) + (3\bold{i} - 2\bold{j}) + (-\bold{i} -3\bold{j}) = (2+3-1) \bold{i} +(1-2-3)\bold{j} = 4 \bold{i} -4\bold{j} \mbox{ N}

$

The the acceleration $\displaystyle \bold{a} = \bold{V}/m$

2. let the tension be $\displaystyle \bold{T}$ then the total force on the first particel, and hence the acceleration is:

$\displaystyle

\bold{T}-m_1\bold{g} = m_1 \bold{a_1}

$

and for the second particle:

$\displaystyle

\bold{T}-m_2\bold{g} = m_2 \bold{a_2}

$

but $\displaystyle \bold{a_2} = -\bold{a_1}$ so:

$\displaystyle

\bold{T}/m_2-\bold{g} = -[\bold{T}/m_1-\bold{g}]

$

which can then b solved for $\displaystyle \bold{T}$

RonL - May 24th 2007, 04:22 AMtopsquark
Start by drawing a Free-Body-Diagram for the ball.

I have a +x axis to the right and a +y axis upward. There is a weight (w) acting straight downward, a tension (T) acting at 50 degrees above the -x axis, and an applied force (F) of 50 N acting in the +x direction.

Since the ball is in equilibrium we know that

$\displaystyle \sum F_x = 0$

$\displaystyle \sum F_y = 0$

So:

$\displaystyle \sum F_x = -Tcos(50) + F = 0$

which implies

$\displaystyle T = \frac{F}{cos(50)} = \frac{50 \, N}{cos(50)} = 77.7862 \, N$

and

$\displaystyle \sum F_y = Tsin(50) - w = 0$

which implies

$\displaystyle w = Tsin(50) = \frac{F}{cos(50)} \cdot sin(50) = F tan(50)$

$\displaystyle = (50 \, N)tan(50) = 59.5877 \, N$

-Dan - May 24th 2007, 12:41 PMcarlasaderthanks alot
well i was having alittle trouble figuring out stuff ,thanks alot ...if u can help me with the rest of the problems i will be greatful ....thank you !!:)