Frank pushes with a force of 620 N on a filing cabinet with a mass of 60 g. The cabinet doesn't move What can be inferred?
A. There are no other forces acting on the filing cabinet.
B. The static friction force of the floor and cabinet is greater than 620 N.
C. The net force of the cabinet is greater than 620 N.
D. The friction force of the floor and cabinet is less than 620 N.

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?