Can yall help me please?? I can't get it wrong!

Modify the equation fδt=δ (mv) to find the force of friction.

Quantum mechanics applies to subatomic, atomic, nanometer-size, and micrometer-size systems. nanometer, micrometer, and kilometer-size systems. atomic, nanometer-size, and micrometer-size systems. subatomic, atomic, and nanometer-size systems.

When solid surfaces slide over each other the kind of friction that occurs is called friction