Answer:
[tex]6.046N[/tex]
Explanation:
The net force exerted on the mass is the sum of tension force and the external force of gravity.
[tex]F_n_e_t=F_g+F_t[/tex]
[tex]F_t[/tex] is the tension force.[tex]F_g=9.8N/kg[/tex] is the force of gravity.
[tex]F_n_e_t=ma_c=mv^2/r\\[/tex]
where [tex]r[/tex] is the rope's radius from the fixed point.
From the net force equation above:
[tex]F_t=F_n_e_t-F_g\\=mv^2/r-mg\\=0.4\times(8.5^2/2.9)-0.4\times9.8\\=6.046N[/tex]
Hence the tension force is 6.046N
