Air • Amount • Attracts • Between • Causes • Contact • Counting • Determined • Distance • Dividing • Downward • Each • Exists • Factors • Fast • Fluids • Friction • Gases • Helps • Include • Leftward • Liquids • Lubricants • Measure • Measuring • Medium • More • Motion • Move • Nature • Normal • Number • Objects • Opposes • Positive • Presence • Present • Pressing • Required • Rest • Reverse • Rightward • Rolling • Shape • Sliding • Slow • Solids • Surfaces • Times • Touched