Q1: A projectile is thrown at an angle a to the horizontal with α velocity v. It will have the maximum centripetal acceleration

ANS:A - at the start

Projectile: Pv and Ph forces act simultaneously.

Any vehicle wheel has max acceleration at it starts only...
Therefore, it has max acceleration at the start only. At the start of projectile where are must be less and are is inversely proportional to acceleration so at the start of the projectile the acceleration is maximum. Centripetal acceleration = v^2/r.
Velocity is Zero at the top and increases towards the ground, reaches maximum before strikes it.
For max acceleration --> max velocity --> as it strikes the ground.