Answer: F = 98N
Explanation: The shaft have to sustain the pulley, the cord and the two masses. The pulley and the cord have negligible masses, so, they have negligible weight.
The two masses have two vertical forces acting on them: force of traction because of the cord and force due to gravitational force, also known as weight.
So, the vertical force the shaft has to support is the sum of the weight of each mass:
[tex]F_{net}=F_{g}_{1}+F_{g}_{2}[/tex]
[tex]F_{net}=m_{1}.g+m_{2}.g[/tex]
[tex]F_{net}=g(m_{1}+m_{2})[/tex]
[tex]F_{net}=9.8(7+3)[/tex]
[tex]F_{net}=[/tex] 98
The vertical force that supports the whole system is 98 N.