The chain on the swing should be 8.0 m long .
Centripetal Acceleration ( a ) = v ² / r ........... Eq. 1
It is given that ,
a = 21 m / s ²
v = 13 m / s
Now , using the values of ' a ' and ' v ' i.e. 21 m / s ² & 13 m / s respectively in Eq. 1
a = v ² / r
21 = ( 13 ) ² / r
21 = ( 13 x 13 ) / r
r = ( 13 x 13 ) / 21
r = 8.047 m
⇒ r = 8.0 m ( rounded off to nearest tenth )
Hence , the chain on the swing should be 8.0 m long .
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