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General Physics

Physics Tutor

Escape Velocity

What is the escape velocity of a rocket launched from position A, the center of the three planet system depicted in the figure. Each planet has mass M, radius R, and the distance between the center of any planet and position A is r. 

A Ball is Thrown

General Physics Class Assignments

What is Magnitude of Angle between Vectors?

The vector A = (A_x , A_y) = ( +2.0 m, +2.0 m) and the vector B = (B_x , B_y) = ( +1.0 m, -1.0 m).
What is the magnitude of the angle between the vectors A and B? 

Intermediate calculations (by Google Search):
arccos(((2.05 * 1.05) - (1.95 * 0.95)) / (sqrt(2.05 * 1.95) * sqrt(0.95 * 1.05))) = 81.3594657 degrees
arccos(((1.95 * 0.95) - (2.05 * 1.05)) / (sqrt(2.05 * 1.95) * sqrt(0.95 * 1.05))) = 98.6405343 degrees

Solution: 90 ± 9 degrees