Balance of vertical forces problem. Three balanced forces pull on a ring that is centered over a force table. Two forces F1 and F2 are due to weights hanging from pulleys. A frictionless pulley changes the direction of a force without altering its magnitude. The third force F3 is applied by a string that passes over a pulley and pulls on the force transducer.

Question

Balance of vertical forces problem.  Three balanced forces pull on a ring that is centered over a force table. Two forces F1 and F2 are due to weights hanging from pulleys. A frictionless pulley changes the direction of a force without altering its magnitude. The third force F3 is applied by a string that passes over a pulley and pulls on the force transducer.

EXAMPLE:
>From the balance of vertical forces, derive the expected value of theta2 in terms of m1, m2, and theta1. 
[Answer: theta2=sin^(-1)[m1sin1/m2).]

Which equation is NOT used in the derivation?

A. F=ma
B. F=mg
C. Fg=Fsin(theta)
D. Fg=Fcos(theta)

Alec · Accepted Answer

The answer is D. Fg=Fcos(theta)