- #1

- 31

- 0

## Homework Statement

A block of mass M is attached to a light string. The string passes over a massless, frictionless pulley and is attached to a solid uniform ball of mass 3M. The ball is at rest and completely submerged in a fluid as shown. What is the ratio of the density of the fluid to the ball?

## Homework Equations

Fb = (rho)Vg

Fg = mg

## The Attempt at a Solution

The forces acting upward must balance the forces acting downward on the ball. Thus,

Fb + Tension = Fg

Then,

(rho)Vg + T = 3Mg

We know that the tension in the string is equal to M because it is keeping the block at rest. Thus,

(rho)Vg + Mg = 3Mg

(rho)Vg = 2Mg

Divide both sides by Vg and we obtain:

*(rho(fluid)) = 2(rho(ball))*This is not the correct answer. Can someone explain what I'm doing wrong?