What force must be applied to move a 251 kg rock on a pavement like surface

If the rock is just sitting there and you want to SLIDE it, then you have to push it with a force of at least

(251 kg) x (9.8 m/s²) x (μ) =

(2,459 Newtons) x (the coefficient of static friction on that surface)

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.