- #1
BvU said:Sigh... after wasting some time on this, I conclude that surd26 is ##\sqrt { 26}## and you use it to decompose the 39 N into x and y components. For the ##\ \vec r\ ## in ##\ \vec \tau = \vec r \times \vec F\ ## you then take ##\ \vec r = (1,3)\ ##. Shouldn't that be ##\ \vec r = (0,3) \ ## ? It gives yet another answer, but I wouldn't trust a book answer in a book that let's 1 m be represented by a square ( )
PS I get what mjsd gets. The bat types faster ...
werson tan said:sorry , the book contain error , the 1m should be 12m on the 39N triangle . I have redo the question .
20(4) -39(5/13)(3) +39(12/13)(1) -60(3/5)(1)+60(4/5)(3)
=179N
I know what u mean . In the above steps , I have resolved the 60N in this way( black and red) , whereas the green colour one is the resolution of force done by you .mjsd said:As I said in my first post...
39(12/13)(1) should NOT be there as the (1) is actually (0)...can you see that?
and
60(4/5)(3) is actually 60(4/5)(2)
once you have got these
you should get 95 Nm for your answers
yes , i know why it should be 39(12/13)(0), now my question is why can't I resolve the force in the way that i have posted earlier?werson tan said:I know what u mean . In the above steps , I have resolved the 60N and 39N in this way( black and red) , whereas the green colour one is the resolution of force done by you .
For the 39N force , I have resolved the force in this way ( black and red)
A moment about a point using graph paper is a way to calculate the turning effect of a force around a specific point. It is commonly used in physics and engineering to understand the balance of forces in a system.
To calculate a moment about a point using graph paper, you need to measure the perpendicular distance between the force and the point of rotation. This distance is then multiplied by the magnitude of the force to determine the moment.
The units used to measure a moment about a point depend on the units used to measure the force and distance. Generally, the SI unit for moment is Newton-meters (Nm) or Joules (J).
A moment about a point is represented by a vector, with the direction of the vector indicating the direction of rotation and the length representing the magnitude of the moment. The point of rotation is typically marked on the graph paper as well.
Calculating moments about a point using graph paper is important because it allows us to understand the balance of forces in a system and determine the stability of an object. It is also essential in designing structures and machines to ensure they can withstand external forces without tipping or breaking.