This angle is the critical angle above which total internal reflection occurs in a material whose refractive index equals the square root of 2.
This angle is the critical angle above which total internal reflection occurs in a material whose refractive index equals the square root of 2. The worldline of an object moving at the speed of light makes this angle with respect to the y-axis on a Minkowski diagram. For a granular material with a coefficient of static friction of 1, this is the value of the angle of repose. A projectile launched at this angle from the horizontal will (*) maximize its range for a given initial speed. Doubling this angle gives the angle between a normal force and the friction force it produces. For 10 points, give this angle equal to pi over 4 radians, which is the measure of both acute angles in an isosceles right triangle.
This angle is the critical angle above which total internal reflection occurs in a material whose refractive index equals the square root of 2.
45 degrees [or pi over 4 radians before it’s mentioned] &lt;SE&gt;