Four uniform spheres, with masses mA = 200 kg, mB = 250 kg, mC = 1700 kg, and mD = 100 kg, have (x, y) coordinates of (0, 50 cm), (0, 0), (-80 cm, 0), and (40 cm, 0), respectively. What is the net gravitational force F2 on sphere B due to the other spheres?

Respuesta :

Answer:

[tex]F_2=2.43\times10^{-19}\ N[/tex]

[tex] \theta=21.496^{\circ}[/tex] in the anticlockwise direction from the positive x- axis.

Explanation:

Given are the masses of various spheres with their names in subscript:

  • [tex]m_A=200\ kg[/tex]
  • [tex]m_B=250\ kg[/tex]
  • [tex]m_C=1700\ kg[/tex]
  • [tex]m_D=100\ kg[/tex]

Now their respective coordinate positions (in cm) are as given below:

  • [tex]P_A=(0,50)[/tex]
  • [tex]P_B=(0,0)[/tex]
  • [tex]P_C=(-80,0)[/tex]
  • [tex]P_D=(40,0)[/tex]

Now force on B due to A:

[tex]F_{BA}=G\times \frac{200\times 250}{50^2}[/tex]

[tex]F_{BA}=20G\ N[/tex]

Now force on B due to C:

[tex]F_{BC}=G\times \frac{1700\times 250}{80^2}[/tex]

[tex]F_{BC}=66.406G\ N[/tex]

Now force on B due to D:

[tex]F_{BD}=G\times \frac{100\times 250}{40^2}[/tex]

[tex]F_{BD}=15.625G\ N[/tex]

We observe that the forces due to masses  C&D act opposite in direction.

So, the net force in the x-direction:

[tex]F_x=F_{BC}-F_{BD}[/tex]

[tex]F_x=66.406G-15.625G[/tex]

[tex]F_x=50.781G\ N[/tex] in the positive x-direction

We have only one force in y-direction due to mass A.

So,

[tex]F_y=20G\ N[/tex] in the positive y-direction.

Now the net force:

[tex]F_2=\sqrt{F_y^2+F_x^2}[/tex]

[tex]F_2=\sqrt{(20G)^2+(50.781G)^2}[/tex]

[tex]F_2=54.5776G^2\ N[/tex]

[tex]F_2=2.43\times10^{-19}\ N[/tex]

Now the direction of this force with respect to x-axis:

[tex]tan\ \theta=\frac{F_y}{F_x}[/tex]

[tex]tan\ \theta=\frac{20G}{50.781G}[/tex]

[tex] \theta=21.496^{\circ}[/tex] in the anticlockwise direction from the positive x- axis.

Answer:

3.64 x 10^-5 N

Explanation:

mA = 200 kg

mB = 250 kg

mc = 1700 kg

mD = 100 kg

Force on B due to A

[tex]F_{A}=\frac{Gm_{A}m_{B}}{0.5^{2}}[/tex]

[tex]F_{A}=\frac{6.67\times10^{-11}\times200\times250}{0.5^{2}}[/tex]

FA = 1.334 x 10^-5 N

Force on B due to C

[tex]F_{C}=\frac{Gm_{C}m_{B}}{0.8^{2}}[/tex]

[tex]F_{C}=\frac{6.67\times10^{-11}\times1700\times250}{0.8^{2}}[/tex]

FC = 4.43 x 10^-5 N

Force on B due to D

[tex]F_{D}=\frac{Gm_{D}m_{B}}{0.5^{2}}[/tex]

[tex]F_{D}=\frac{6.67\times10^{-11}\times100\times250}{0.4^{2}}[/tex]

FD = 1.042 x 10^-5 N

FD and Fc are opposite to each other, so net of Fc and FD is F'.

F' = (4.43 - 1.042) x 10^-5 N towards left

F' = 3.39 x 10^-5 N

Now F' and FA are perpendicular to each other, So net force on B due to all other

[tex]F=\sqrt{F'^{2}+F_{A}^{2}}[/tex]

[tex]F=\sqrt{1.334^{2}+3.39^{2}}\times 10^{-5}[/tex]

F = 3.64 x 10^-5 N

Thus, the net force on B due to other is 3.64 x 10^-5 N.