Answer:
The final acceleration becomes (1/3) of the initial acceleration.
Explanation:
The second law of motion gives the relationship between the net force, mass and the acceleration of an object. It is given by :

m = mass
a = acceleration
According to given condition, if the mass of a sliding block is tripled while a constant net force is applied. We need to find how much does the acceleration decrease.

Let a' is the final acceleration,

m' = 3m



So, the final acceleration becomes (1/3) of the initial acceleration. Hence, this is the required solution.
More energy is being used in the movement
With its apparent magnitude
Atmospheric pressure is molecular's heavy. So the total number of molecules decreases by going up the surface of the earth. Ok?