Question

Why is acceleration taken negative in ground to ground projectile motion?

Answer 1

Explanation:

This is simple because the direction of motion is upwards...

See , The direction of motion is always taken positive:-

Therefore the acceleration of gravity i.e. 9.8m/s^2 is taken negative (-g).

So in projectile motion before getting on the surface the object retarded due to negative acceleration i.e. gravity .....

I hope u understand!!:)