Asingle conservative force fx = (6.0x  12) n (x is in m) acts on a particle moving along the x axis. the potential energy associated with this force is assigned a value of +20 j at x = 0. what is the potential energy at x = 3.0 m?

Explanation:

Potential energy is minus the integral of Fdx.  Doing the integration yields:

so

Now for x=3.0m

the independent variable, or the one that is intentionally manipulated is the speed.

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.