Consider the following distribution of objects: a 5.00-kg object with its center of gravity at (0, 0) m, a 3.00-kg object at (0, 4.00) m, and a 4.00-kg object at (3.00, 0) m. Where should a fourth object of mass 8.00 kg be placed so that the center of gravity of the four-object arrangement will be at (0, 0)?

Respuesta :

Answer:

(-1.5,-1.5)m

Explanation:

we know that:

[tex]X_{cm} = \frac{m_1x_1+m_2x_2....m_nX_n}{m_1+m_2...m_n}[/tex]

where [tex]X_{cm}[/tex] is the location of the center of gravity in the axis x, [tex]m_i[/tex] is the mass of the object i and [tex]x_i[/tex] the first coordinate of center of gravity of object i.

so:

[tex]0 = \frac{(5kg)(0)+(3kg)(0)+(4kg)(3)+(8kg)x_4}{5kg+3kg+4kg+8kg}[/tex]

Where [tex]x_4[/tex] is the first coordinate of the center of gravity for the fourth object.

Therefore, solving for [tex]x_4[/tex], we get:

[tex]x_4 = -1.5m[/tex]

At the same way:

[tex]Y_{cm} = \frac{m_1y_1+m_2y_2....m_ny_n}{m_1+m_2...m_n}[/tex]

where [tex]Y_{cm}[/tex] is the location of the center of gravity in the axis y, [tex]m_i[/tex] is the mass of the object i and [tex]y_i[/tex] the second coordinate of center of gravity of object i. replacing values we get:

[tex]Y_{cm} = \frac{(5kg)(0)+(3kg)(4)+(4kg)(0)+(8kg)y_4}{5+3+4+8}[/tex]

Where [tex]y_4[/tex] is the second coordinate of the center of gravity for the fourth object.

solving for [tex]y_4[/tex]:

[tex]y_4 = -1.5m[/tex]

It means that the object of mass 8kg have to be placed in the  

coordinates (-1.5,-1.5) m.