In the figure provided, a 255 kg crate, to the right of the pulley, is released from rest and begins to fall to the ground. If the mass on the left is m=100. kg, what is the magnitude of the acceleration of the 255 kg crate? Assume the rope and pulley are massless.

No diagram, assuming to the right is fall straight down, one on the left is horizontal, no friction.

F=ma
255*g=(255+100) a
solve for a