Physics I Gravity

4 Known Forces: Gravity Electromagnetic Strong Nuclear Force – holds protons and neutrons together in atomic nuclei; also holds quarks and gluons together in protons and neutrons Weak Nuclear Force – results in beta decay (a type of radioactive decay) where an electron or positron is emitted

Newton – He’s the Man! Newton compared falling apple to “falling” moon The apple and moon were both affected by Earth

Universal Law of Gravitation “Everything pulls on everything else in a beautifully simple way that involves only mass and distance,” p.162.

Inverse Square Law Masses are directly proportional to force of gravity If you double the mass of one object you double the force of gravity Distance between objects follows inverse square law If you double the distance between objects you ¼ the force of gravity

Time for some calculations!