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## Homework Statement

The diagram shows a particle A of mass m which can move on the rough surface of a plane inclined at an angle theta to horizontal ground, where theta = arcsin 0.6. A second particle B of mass 2m hangs freely attached to a light inextensible string which passes over a smooth pulley fixed at D. The other end of the string is attached to A. The coefficient of friction between A and the plane is 1/4. B is initially hanging 3m above the ground and A is 2m from D. When the system is released from rest with the string taut A moves up the plane.

(a) Find the initial acceleration of A.

When B has descended 1m, the string breaks. By using the principle of conservation of energy.

(b) calculate the total distance moved by A before it first comes to rest.

http://img135.imageshack.us/img135/9503/scan0001small.gif [Broken]

## Homework Equations

F=ma

K.e. = 1/2mv

^{2 }

G.p.e = mgh

## The Attempt at a Solution

a) 2mg - T = 2ma

T - cos36.87 = ma

2mg - 0.8mg = 3ma

1.2g = 3a

a = 3.92ms-2

b) mgh = 2mg

2(0.6) = 1.2

I got part a right but b is meant to be 1.5m. Not sure why I ain't getting the right answer...

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