Question

A 12kg mass is placed on a 30° frictionless inclined plane attached to a pulley connected to a hanging mass of 5kg. What is the acceleration of the system?

Answer 1

$12\cdot g\sin30°-T=12\cdot a$

$5\cdot g-T=-5\cdot a \to T=5\cdot g+5\cdot a$

$12\cdot g\sin30°-5\cdot g-5\cdot a=12\cdot a$

$a=(12\cdot9.8\cdot\sin30°-5\cdot9.8)/17=0.58\ (m/s^2)$