What values are equal to zero when an object is not moving

Aman tries to push a box of mass 4 kg with a force of 5 n but the box remains stationary if the coefficient of static friction is 0.45, what is the value of the maximum force of friction?

In positive numbers less than 1, the zeros between the decimal point and a non-zero number are blank significant

In the united states, tornadoes generally occur because of the freezing of ocean water underwater earthquakes meeting of cool and warm air masses shifting of warm and cool ocean currents