If the radius of earth shrinks by 1% & its mass remain same, then acceleration due to gravity on earth 'surface will

Question

If the radius of earth shrinks by 1% & its mass remain same, the acceleration due to gravity on earth 'surface will

Answer 1

The acceleration due to gravity g = GM/r² = 9.8 m/s²
If r reduces by 1%, the new radius becomes r' = 99% of r = 99r/100 = 0.99r
New acceleration due to gravity g' = GM/(0.99r)²
= GM/(0.98r² )
= 1.04 g = 10.19 m/s²

Increase in acceleration due to gravity = 10.19 − 9.8 m/s²
=  0.39 m/s² 
Increase in percentage = 0.39 x 100/9.8 = 3. 97%