Two blocks connected by a cord passing over a small fictionless pulley rest on an double inclined plane (ie a traingle) with static friction coefficient of 0.5 and a kinetic friction coefficient of 0.4. The mass of block A is 100 kg (sitting at 30 degrees), while the mass of block B is 50 kg (sitting at 53.1 degrees).
A. Which way will the system move when the blocks are released from rest?
B. What is the acceleration of the blocks?
For A, we need to look at the forces pulling down on the block right? So for mass A is it, mgsinӨ-u(kinetic)mgcosӨ=151N and for mass B is it, mgsinӨ-u(kinetic)mgcosӨ=274N. So mass B must slide down, while mass A must slide up right?
For B, the F=ma equation for mass A is T-mgsinӨ-u(kinetic)mgcosӨ=ma, while for mass B, it is mgsinӨ-u(kinetic)mgcosӨ-T=ma.
So T-151=100a, meaning T is 151+100a. Plugging into the equation for mass B, 391.8-117.7-(151+100a)=50a. So a=0.821 m/s^2. Is this right?