Go Back   Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

Reply
 
LinkBack Thread Tools Display Modes
Old Oct 21st 2013, 09:15 AM   #1
Junior Member
 
Join Date: Oct 2013
Posts: 6
Hi guys

I have 2 questions and I need your help please ^__^

1: Using components determine the sum of + if = 3 m [N30W] and = 2 m [N10E].

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

Duha is offline   Reply With Quote
Old Oct 21st 2013, 12:05 PM   #2
Forum Admin
 
topsquark's Avatar
 
Join Date: Apr 2008
Location: On the dance floor, baby!
Posts: 2,451
Originally Posted by Duha View Post
1: Using components determine the sum of + if = 3 m [N30W] and = 2 m [N10E].
Please let me be the first to say: "What??" This makes no sense. Can you write out the full problem?

Originally Posted by Duha View Post
2: A force of 3.0 N and 1.0 N act as shown. What is the acceleration of the 6.0 kg mass?

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
__________________
Do not meddle in the affairs of dragons for you are crunchy and taste good with ketchup.

See the forum rules here.
topsquark is offline   Reply With Quote
Old Oct 21st 2013, 12:41 PM   #3
Junior Member
 
Join Date: Oct 2013
Posts: 6
Hi
I`m so sorry with the first question

1) 1: Using components determine the sum of a + b if a = 3 m [N30W] and b = 2 m [N10E].


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.
Duha is offline   Reply With Quote
Old Oct 21st 2013, 02:40 PM   #4
Forum Admin
 
topsquark's Avatar
 
Join Date: Apr 2008
Location: On the dance floor, baby!
Posts: 2,451
Originally Posted by Duha View Post
1) 1: Using components determine the sum of a + b if a = 3 m [N30W] and b = 2 m [N10E].
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
__________________
Do not meddle in the affairs of dragons for you are crunchy and taste good with ketchup.

See the forum rules here.
topsquark is offline   Reply With Quote
Old Oct 24th 2013, 08:36 AM   #5
Junior Member
 
Join Date: Oct 2013
Posts: 6
I`m so sorry for being late

The components of vector b it will be (2 m)*cos(10) and (2 m)* sin(10) ?!
Duha is offline   Reply With Quote
Old Oct 24th 2013, 11:29 AM   #6
Physics Team
 
ChipB's Avatar
 
Join Date: Jun 2010
Location: Morristown, NJ USA
Posts: 2,310
Originally Posted by Duha View Post
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.
ChipB is offline   Reply With Quote
Old Oct 24th 2013, 11:39 AM   #7
Junior Member
 
Join Date: Oct 2013
Posts: 6
And then a + b will be ????
Duha is offline   Reply With Quote
Old Oct 24th 2013, 12:57 PM   #8
Physics Team
 
ChipB's Avatar
 
Join Date: Jun 2010
Location: Morristown, NJ USA
Posts: 2,310
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.
ChipB is offline   Reply With Quote
Old Oct 26th 2013, 09:27 AM   #9
Junior Member
 
Join Date: Oct 2013
Posts: 6
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 is offline   Reply With Quote
Old Oct 30th 2013, 09:27 PM   #10
Junior Member
 
Join Date: Oct 2013
Posts: 6
I solved the first question guys
Could you please now help me with the second one ^__^
Duha is offline   Reply With Quote
Reply

  Physics Help Forum > High School and Pre-University Physics Help > Kinematics and Dynamics

Tags
guys



Thread Tools
Display Modes


Similar Physics Forum Discussions
Thread Thread Starter Forum Replies Last Post
guys .. need help plz ashahos Electricity and Magnetism 0 Jan 8th 2011 12:08 PM


Facebook Twitter Google+ RSS Feed