When forces are balanced: When forces are unbalanced: Net force: Size of the Arrow Friction: Tension force Inertia Spring balance Magnetic force Lever Machine Helpful: Unhelpful: Applied force Inclined Plane Examples Parachute Newtons Simple Machines Gravity Mass on the moon Weight on the moon Complex machines First Class Lever Second Class Lever Third Class Lever If I changed the surface, how would the angle change with smooth/rough surfaces? Examples Examples Examples