Help plz need the answer

If the speed of a particle triples ,by what factor does its kinetic energy increase?

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?

The ph is the a.independent variable b.the dependent variable c.control group