everytime there is acceleration if there a force behind it or vice versa ?? is newtans law applicable all the time ?

Question

anonymous · Answer

Newtons laws and its applicability depends upon the frame of reference from which we are analyzing a motion . Newtons laws are valid in all inertial (not accelerating)
reference frames. So for an observer in an inertial reference frame acceleration is always caused by some applied force

anonymous · Answer

The force is product of mass and acceleration, or more correctly the force is a product of mass and change of speed in time $$F=m*dv/dt=m*a$$, without acceleration there is no force and "vice versa".

trancenova · Answer

On earth are we always accelerating due to gravity?

anonymous · Answer

Due to gravity no, because there is opposite force, the force that ground creates on you when you are standing on it.