Does anyone know what number 6 a, b,c or d is

Rubber on floor tile has a coefficient of kinetic friction of 1.0 and a coefficient of static friction of 2.0. how much force would a 3.5 lb. robot need to produce in order to start moving?

Mike walks 100 meter north, then walks 30 meters south. after this, he walks another 10 meters north. what is the magnitude of his total displacement during this walk,in meters?

In all trials, the magnitude of the final velocity for g1 + g2 was less than the magnitude of any initial velocity. as mass increased, what happened to the velocity? the velocity decreased. the velocity increased. the velocity of g1 + g2 could not be measured. the velocity was not affected by the mass increase.