A) 8.04 N
B) 11.96N
C) 10 N
D) 1.96N
Correct Answer: A
Solution :
When a body tied to the end of a string is rotated in a vertical circle, the speed of the body is different at different points of the circular path when body is at highest point A, it is acted upon by two forces weight mg of the body and tension\[{{T}_{A}}\]in the string. \[\therefore \]\[{{T}_{A}}+mg=\]centripetal force\[=\frac{mv_{A}^{2}}{r}\] \[\Rightarrow \] \[{{T}_{A}}=\frac{mv_{A}^{2}}{r}-mg\] Given, \[m=0.2\,kg,r=0.5m,\,{{v}_{A}}=5\,m/s\] \[\therefore \] \[{{T}_{A}}=\frac{0.2\times {{(5)}^{2}}}{0.5}-0.2\times 9.8\] \[{{T}_{A}}=10-1.96\] \[{{T}_{A}}=8.04N\]You need to login to perform this action.
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