Hey!

As we know,

Vx(velocity in x direction) =10cos60 =5m/s

Vy (velocity in y direction) =10cos30 =53m/s

Velocity after t=1 second

Vx=5m/s (velocity in x direction will remain same)

Vy=(5sqrt3−10) m/s =10−5sqrt3

An=(v^2)/R

Which means

R = (Vx^2+Vy^2) /An

Which means R is (25+100+75−100sqrt3) / 10Cosθ

tanθ=(10−5sqrt3) /5

tanθ=2−sqrt3

θ=15 degrees

Then,

R=[100(2−sqrt3)] /10cos15

R =2.8m

Hope it helped to clear your delimma.

Thank you.