Question

answer the following

Answer 1

no this cant happen as when an object is in constant acceleration then then when he need to change its direction of motion and for this he need to change its acceleration but it is given constant for eg  when a car is driving forward a driver first stops the car then it means change its acceleration and then he move backword

Answer 2

Yes, for example when you throw a ball vertically up and when it reaches till top the acceleration due to gravity is constant but on reaching at top it changes its direction downwards.