The force you apply to pull the box is weak.
Explanation:
- We know that, F=ma, where F is the force, m is the mass of the object and a is the acceleration with which the object moves.
- Hence, as per the equation given above the applying force should be either equal to or greater than the mass of the object.
- If it is not the case, then the object will not move. So, for the object to move we need to apply a greater force, when the applied force is greater then the object moves faster and vice versa