Step-by-step explanation:
From the curve given in the attachment,
a) minimum speed v0 required if the car is to travel beyond the top of the hill
climb to the top = 5.4 m
Therefore,
![V_0=√(2gh)](https://img.qammunity.org/2021/formulas/physics/college/ndm1htqpza9a914ng01f5w8nrdciwgfuhw.png)
= 10.29 m/s
b) No, we cannot affect this speed by changing the depth of the valley to make the coaster pick up more speed at the bottom as this speed does not depend upon depth of the valley.