
Define pressure.
Use the answer to (a)(i) to show that the SI base units of pressure are 
A horizontal pipe has length
and a circular cross‑section of radius
. A liquid of density
flows through the pipe. The mass
of liquid flowing through the pipe in time
is given by:

where
and
are the pressures at the ends of the pipe and
is a constant.
Determine the SI base units of
.