- #1

oMattz

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1. Homework Statement

1. Homework Statement

A block, of mass M1, on the rough slope shown is attached to another mass M2 by a light, inextensible string which passes over a frictionless pulley as shown in the diagram (the coefficient of friction between the block and the slope is u ). The block is released from rest. Find an expression for the height of the block above the bottom of the slope as a function of time. (You should consider the full range of behaviour that may happen for different values of the parameters).

## Homework Equations

[/B]

F(gravity down slope) = mgsin(theta)

F(friction down slope) = umgcos(theta)

f=ma

s = ut +1/2at^2

## The Attempt at a Solution

Force of gravity on block is m1gsin(theta)

Force of friction on block is um1gcos(theta)

Force needed to push block up slope at constant speed = m1gsin(theta) + um1gcos(theta)

If M2g > Force needed then block will accelerate up slope with a=(M2g-(m1gsin(theta) + um1gcos(theta)))/m1

vertical component of that acceleration = asin(theta)

height = ut + 1/2at^2

height = 0.5*(m2g-(m1gsing(theta) + um1gcos(theta)))/m1)sin(theta)*t^2

I'm pretty sure this answer is wrong as it is so complex, but would just like either confirmation that it is right/wrong and where to go