Question

Give one example each of positive acceleration and negative acceleration...... pls answer it...

Answer 1

Positive acceleration=​ A bus or car moving with increasing speed has positive acceleration. We can say that it is accelerating with the direction of travel.
Negative acceleration=​In the above example, if we apply the break, the speed of the car decreases. Then it has negative acceleration. So we can say that it is decelerating. 
Uniform acceleration=A freely falling body (since it has a uniform acceleration equal to the acceleration due to gravity of the earth).

Answer 2

the examples are:

a) dropping something

b) applying breaks to a running car

c) A moving train

d) vehicles in traffic.