The centripetal acceleration is given by:
[tex]a_c = \frac{v^2}{r} [/tex]
where
v is the velocity of the object
r is the radius of the trajectory
Initially, the car has an acceleration of [tex]a_c = 20 m/s^2[/tex] and the radius of its trajectory is [tex]r=5 m[/tex], so its velocity is
[tex]v= \sqrt{a_c r}= \sqrt{(20 m/s^2)(5 m)} =10 m/s [/tex]
Then the radius is increased to r=10 m, so the new centripetal acceleration is:
[tex]a_c = \frac{v^2}{r}= \frac{(10 m/s)^2}{10 m}= 10 m/s^2 [/tex]
