A .70 m tall barrel is closed on top except for a thin pipe extending 5.3m up from the top. When the barrel is filled with water up to the base of the pipe the water pressure on the bottom of the barrel is 6.9 kPa.

To find the water pressure at the bottom of the barrel, we'll use the hydrostatic pressure formula:

Pressure = Density x Gravity x Height

First, let's convert the height of the water column to meters. The barrel is 70 cm tall, which is equal to 0.70 m.

Now, we need to find the density of water and the acceleration due to gravity.

The density of water is approximately 1000 kg/m³.

The acceleration due to gravity is approximately 9.8 m/s².

Now, we can substitute these values into the formula:

Pressure = 1000 kg/m³ x 9.8 m/s² x 0.70 m

Calculating this gives us the pressure at the bottom of the barrel.

Pressure = 6860 Pa

To convert this to kilopascals (kPa), we divide the pressure by 1000:

Pressure = 6.860 kPa

Therefore, the water pressure at the bottom of the barrel is approximately 6.860 kPa.