A mass of 0.2kg is whirled in a horizontal circle of radius 0.5m by a string inclined at 30° to the vertical. Calculate the tension in the string and the speed of the mass in the horizontal circle?

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Answer 1 · 2018-07-28T09:20:55

The tension is #=2.26N# and the speed is #=1.68ms^-1#

Let the tension in the string be #=T (N)#

Then,

Resolving in the vertical direction

#Tcostheta=mg#

The acceleration due to gravity is #=9.8ms^-2#

#T*cos30º=0.2*9.8#

#T=(0.2*9.8)/(cos30)=2.26N#

Resolving in the horizontal direction

#Tsintheta=mv^2/r#

Therefore,

#v^2=(rTsintheta)/(m)#

#v=sqrt((rTsintheta)/(m))#

#=sqrt((0.5*2.26*sin30)/0.2)#

#=1.68ms^-1#