Problem 1
An ideal Atwood machine has masses and hanging on opposite sides of a light inextensible string over a frictionless, massless pulley; take as the gravitational acceleration and assume the system is released from rest. The heavier mass moves downward, with both masses having the same acceleration magnitude because the string length is fixed. (a) Find the acceleration. (b) Find the string tension. (c) Find the speed after the heavier mass has descended a distance .
problems.proof.stepOf
problems.proof.analysis
This equation expresses the physical law governing the system. It incorporates the stated constraint rather than treating the relevant quantities as independent.
problems.proof.pitfall. Check the sign convention and physical case carefully; do not use a formula for a different motion or geometry.