21We know
s=ut+1/2at2
comparing with given equation:
u=2,a=1;
This a is tangential acceleration.
But it is given that as t varies a also varies,therefore there must be some radial component(ie centrifugal acceleration)that varies with time
Let this radial acceleration be a'
a'2=v2/r=(u+a*2)2/r=16/r
similarly a'5=49/r
Now,√(162/r2+1)/√(492/r2+1)=1/2
Solving:
r=3√51