Answer:
4R
Step-by-step explanation:
The centripetal acceleration a is given by a = v²/r where V = speed of object and r = radius of circle. Now, it is given that V = speed of car = V and radius of circle = R, so its centripetal acceleration a = V²/R.
Now, if the speed is doubled to V' = 2V with the same centripetal acceleration, we find the new radius of the curve R' from
a = V'²/R'
R' = V'²/a
R' = (2V)² ÷ V²/R
R' = 4V²R/V²
R' = 4R
So, the new radius is 4 times the initial radius.