A 5.00-kg block is initially moving to the right with a speed of 2 m/s. It was pushed to the left which made it decrease its speed to 1 m/s. What is the change in the block's momentum? zero
3-15 kg m/s
5kg m/s
10 kg m/s

Yes

Amagnetic field "does not" interact with stationary electric charges. so, a.hope my answer you : )

Answer(a)   the matererials that are in contact, the two materials and the nature of their surfaces/// (b)/// the force pushing the two surfaces together, pushing the surfaces together causes the more of the asperities to come together and increases the surface area in contact with each other