Physics

# Key Equations

PhysicsKey Equations

### 4.2Newton's First Law of Motion: Inertia

 Newton's first law of motion or $ΣF=0 ΣF=0$

### 4.3Newton's Second Law of Motion

 Newton’s second law of motion $F net =ma F net =ma$ or $ΣF=ma ΣF=ma$ Newton’s second law of motion to solve acceleration Newton’s second law of motion to solve weight $W=mg W=mg$

### 4.4Newton's Third Law of Motion

 normal force for a nonaccelerating horizontal surface $N=mg N=mg$ tension for an object at rest $T=mg T=mg$