Can the velocity of an object change when it’s acceleration is constant? if so give example. if not explain

Yes the velocity changes.

Explanation:

Acceleration is defined as the rate of change of velocity.Acceleration can be uniform and non uniform. In uniform acceleration the velocity changes at a uniform rate and in non uniform acceleration it changes at a non uniform rate.

In the given case it is uniform acceleration. So the velocity will change at a uniform rate .

Hence at every instant velocity will keep changing.

b would be the answer

find the sum of the two horizontal vectors and the sum of the two vertical vectors

isoceles right angled triangle