Fluids II Review

Question 1

1. Define Archimedes’ Principle

Answer 1

An object submerged in a fluid is buoyanced by a force equal to the weight of the fluid displaced.

Question 2

2. List two factors that affect the buoyant force acting on an object placed in a liquid.

Answer 2

Density and volume submerged of the object.

Question 3

9. What does Pascal’s Principle say?

Answer 3

The pressure exerted on a fluid is transmitted everywhere through the fluid.

Question 4

13. How does the density of the fluid affect the buoyant force on a boat?

Answer 4

The greater density of the fluid, the greater the buoyant force of the boat will be.

Question 5

14. What happens to the water line of a boat when it goes from fresh to salt water?

Answer 5

The water line descends, less of the boat is submerged.

Question 6

29. How does density of the fluid and of the object determine whether or not the object will float?

Answer 6

The average density of the fluid must be higher than the object’s density for it to float.

Question 7

A rock is weighed in air and weights 13N. It’s weighed again in water and is found to be 5N. Buoyance force?

Answer 7

8N

Question 8

What is meant by water seeks its own level

Answer 8

Water will flow until pressures equalize. (Same depth = same pressure)

Question 9

11. Describe the shape of a dam and why it’s made that way.

Answer 9

Dams are built in curves or arches, where it’s thicker at the bottom and thinner at the top. The higher pressure and force is at the bottom, at the deepest depth of the water, so the dam needs most reinforcement there. It saves money instead of having the same thickness everywhere in the dam.

Question 10

12. Explain the hydraulic lift.

Answer 10

On one side, small force over small area. On the other, big force over big area. But because of Pascals Principle the pressure will be the same, but different distances moved. The small side’s distance moved will be a lot larger.

Question 11

15. What happens to the water line of a boat when it is in the same water but its empty vs. loaded down with cargo?

Answer 11

An empty boat’s water line is lower than a loaded boat’s. The loaded boat’s weight goes up, so does must the buoyance force, and along with it the volume submerged.

Question 12

27. What is the one major factor that affected how many pennies your foil boat could hold when placed in water?

Answer 12

The volume submerged of the boat.

Question 13

28. What were other problems you had to consider?

Answer 13

The foil’s lack of rigidity , leaks, uneven sides, tallness of the sides (easy to tip over).