### Gravitational Physics

Explore: What is Mass?

To talk about gravity, we need a solid conception of mass itself. In Newtonian gravity, mass appears in two central roles, which we will discern in this quiz:

• The weight of an object is directly proportional to its mass $m$.
• In Newton's second law, an object's mass $m$ controls its response to forces.

When we are calculating the effects of gravity on a falling object, mass takes on both roles simultaneously. In no other classical theory is one quantity endowed with two interpretations; in fact the mysterious dual role of mass is the point of departure for Einstein’s celebrated theory of gravity, general relativity.

Without further ado, let’s begin our exploration of gravity with the mystery of the white room.

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