# Use dimensional analysis to show that increase in g due to lead

1. Apr 27, 2010

### cloudone

1. The problem statement, all variables and given/known data
A clock is placed on a floor covered with lead density $$\rho$$ and thickness d. Use dimensional analysis to show that increase in gravitational field strength at the clock dueo to the layer of lead is proportional to $$Gd\rho$$

2. Relevant equations

3. The attempt at a solution
to show that $$\Delta g = kGd\rho$$

units of $$\Delta g = m s^{-2}$$

units of $$Gd\rho = m^{3}kg^{-1}s^{-2}kgm^{-3}$$

I don't get why they're not the same.

2. Apr 27, 2010

### Stonebridge

You forgot to include the units for d, the thickness.

3. Apr 27, 2010

### cloudone

argh, thanks. I just realized that. I've been thinking dp as differential of p