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 Duha Oct 21st 2013 09:15 AM

Hi guys

1: Using components determine the sum of + if = 3 m [N30°W] and = 2 m [N10°E].

2: A force of 3.0 N and 1.0 N act as shown. What is the acceleration of the 6.0 kg mass?

http://www2.0zz0.com/2013/10/21/16/491079930.gif

 topsquark Oct 21st 2013 12:05 PM

Quote:
 Originally Posted by Duha (Post 22186) 1: Using components determine the sum of + if = 3 m [N30°W] and = 2 m [N10°E].
Please let me be the first to say: "What??" This makes no sense. Can you write out the full problem?

Quote:
 Originally Posted by Duha (Post 22186) 2: A force of 3.0 N and 1.0 N act as shown. What is the acceleration of the 6.0 kg mass? http://www2.0zz0.com/2013/10/21/16/491079930.gif
For this one you'll want to find the net force acting on the block in components in the usual +x and +y directions. Do you know how to do this?

-Dan

 Duha Oct 21st 2013 12:41 PM

Hi :)
I`m so sorry with the first question

1) 1: Using components determine the sum of a + b if a = 3 m [N30°W] and b = 2 m [N10°E].

And the second question, by using sine and cosine for horizontal and vertical
but i don`t know how to sort the solution. :(

Thanks a lot for you.

 topsquark Oct 21st 2013 02:40 PM

Quote:
 Originally Posted by Duha (Post 22191) 1) 1: Using components determine the sum of a + b if a = 3 m [N30°W] and b = 2 m [N10°E].
Let's start simple:
Call East the +x axis and North the +y axis. Then we know that a is 3 m long at an angle of 30 degrees above the -x axis. So if we draw the usual triangles to get the components we have that a_x = - (3 m)*cos(30) and a_y = (3 m)*sin(30).

What are the components of the b vector?

-Dan

 Duha Oct 24th 2013 08:36 AM

I`m so sorry for being late :(

The components of vector b it will be (2 m)*cos(10) and (2 m)* sin(10) ?!

 ChipB Oct 24th 2013 11:29 AM

Quote:
 Originally Posted by Duha (Post 22267) I`m so sorry for being late :( The components of vector b it will be (2 m)*cos(10) and (2 m)* sin(10) ?!
Yes, correct.

 Duha Oct 24th 2013 11:39 AM

And then a + b will be ????

 ChipB Oct 24th 2013 12:57 PM

Add a_x and b_x to get the total x-component, then add a_y and b_y to get the total y-component. The magnitide of the resulting vector is from Pythagoras: sqrt(x^2 + y^2). Its direction is calculated using trig: arctan(angle) = x/y to get angle east or west from north.

 Duha Oct 26th 2013 09:27 AM

So for a_x will be (3 m)*cos(30) + (2 m)*cos(10)
and
a_y (3 m)*sin(30) + (2 m)*sin(10)

is that right ????!!!!

 Duha Oct 30th 2013 09:27 PM

I solved the first question guys :)
Could you please now help me with the second one ^__^

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