- #1

oobgular

- 8

- 0

## Homework Statement

A block has dimensions 0.015 x 0.2 x 0.1 meters and weighs 6 Newtons. A 15mm-diameter jet of water is deflected by the block. Find the flow rate needed to tip the block.

## Homework Equations

Mass conservation: ∂/∂t ∫

_{(control volume)}ρ d∀ + ∫

_{(control surface)}ρv•n dA = 0

Momentum conservation: ∂/∂t ∫

_{(control volume)}ρv d∀ + ∫

_{(control surface)}ρv(v•n) dA = ∫

_{(control surface)}p*ndA + Viscous forces + ∫

_{(control volume)}ρgd∀

## The Attempt at a Solution

I know this is steady state, so the first term in each equation (time derivative of mass in the control volume) is zero. I am trying to use a control volume that follows the streamlines, to make the surface integrals easier. However, I don't know what area to use as the output, or even how to approach finding it. Also, how should I relate the force on the block to the force required to tip the block? I assume it has to do with a Moment balance, but I'm not sure how to do that.

I don't want you to solve the problem for me, just some direction would be nice. Thanks!