# Worksheet: Density and Pressure

In this worksheet, we will practice calculating the density of materials and finding the pressure at a given depth in a liquid of a given density.

**Q4: **

The density of water at a temperature of is
999.84 kg/m^{3},
whereas the density of ice at
is 917 kg/m^{3}.
What pressure would need to be applied to water in a container by the container walls to prevent the water from expanding as it froze?
Use a value of
2.20 GPa for the bulk modulus of water.
Neglect the temperature changes that would result from this pressure.

- A Pa
- B Pa
- C Pa
- D Pa
- E Pa

**Q6: **

What is the density of 18.0-karat gold that is a mixture of 18 parts gold, 5 parts silver, and 1 part copper? (These values are parts by mass, not volume.) Assume that this is a simple mixture having an average density equal to the weighted densities of its constituents.

Density of gold is 19.3 g/cm^{3}.

Density of silver is 10.5 g/cm^{3}.

Density of copper is 8.92 g/cm^{3}.

**Q7: **

A person hits a tennis ball with a mass of 0.058 kg against a wall. The average component of the ball’s velocity perpendicular to the wall is 11 m/s, and the ball hits the wall every 2.1 s on average, rebounding with the opposite perpendicular velocity component.

What is the average force exerted on the wall?

If the part of the wall the
person hits has an area of 3.0 m^{2}, what is the average
pressure on that area?