The centripetal acceleration is given by:
![a_c = (v^2)/(r)](https://img.qammunity.org/2019/formulas/physics/high-school/jjxb4cyl39kfe21y5smn7fxjdjv3a2dik3.png)
where
v is the velocity of the object
r is the radius of the trajectory
Initially, the car has an acceleration of
![a_c = 20 m/s^2](https://img.qammunity.org/2019/formulas/physics/high-school/ly83j7a01zp628tuaxlivtentrvl44sfsv.png)
and the radius of its trajectory is
![r=5 m](https://img.qammunity.org/2019/formulas/physics/high-school/5h6g63z3iocy5j5tkluvhf7lsdm9ssf70p.png)
, so its velocity is
![v= √(a_c r)= √((20 m/s^2)(5 m)) =10 m/s](https://img.qammunity.org/2019/formulas/physics/high-school/3glsb3rms1tx6xzgm6jln60u3uzh7fho6g.png)
Then the radius is increased to r=10 m, so the new centripetal acceleration is:
![a_c = (v^2)/(r)= ((10 m/s)^2)/(10 m)= 10 m/s^2](https://img.qammunity.org/2019/formulas/physics/high-school/xa1egc8vh65dasgbrl26ktjkl3erbal1t2.png)