If the mass of a sliding block is tripled while a constant net force is applied, by how much does the acceleration decrease?

As we know that if a rock is sliding under the influence of some external force then By Newton's II law we have

now we will have

now we know that if force remains constant while we tripled the mass of the block then

new acceleration of the block will be given as

so here the acceleration of the block will be decreased by 3 times

need to see circuit to get time constant

e/c, where e is its total energy