FLUID MECHANICS

Question 1

what are the 2 type of force acting on object by fluid and its due to what

Answer 1

Buoyant force
Due to immersion

Dynamic force
Due to relative motion in fluid

Question 2

what is buoyant force

Answer 2

a vertical, upward-directed force acting upon an object that is submerged or partially submerged in a fluid.

Buoyant force is the difference between the force acting upward on the cube and the force acting downward on the cube.

Question 3

what is archimedes principle

Answer 3

a body submerged in a fluid will be buoyed up by a force that is equal in magnitude to the weight of the displaced water.

Question 4

the size of buoyant force is equal to what

Answer 4

the weight of the volume of fluid displaced by the object. This depends on how much water is pushed out of the way by the object.

Question 5

Two key concepts of pressure needed to understand buoyant force

Answer 5

All points of a submerged body, at a given depth, will experience the same pressure.
Pressure increases in large increments with relatively small changes in depth.

Question 6

If the cube of material weighs more than the cube of water, what happen

Answer 6

the buoyant force acting upward is less than the weight acting downward, and the cube will accelerate downward.

Question 6

If the cube of material weighs more than the cube of water, what happen

Answer 6

the buoyant force acting upward is less than the weight acting downward, and the cube will accelerate downward.

Question 7

If the cube of material weighs less than the cube of water,

Answer 7

the buoyant force acting upward is more than the weight acting downward, and the cube will accelerate upward

Question 8

If the cube of material weighs the same as the cube of water,

Answer 8

the buoyant force acting upward equals the weight acting downward, and the cube is in equilibrium.

Question 9

An object with a density less than the fluid it is immersed in will sink or float.

Answer 9

float

Question 10

Whether or not something floats is determined by

Answer 10

the volume of the object immersed and the weight of the object compared to the weight of the same volume of water

Question 11

Something with a specific gravity of 1.0 or less will sink or float.

Answer 11

float

Question 12

what is center of buoyancy

Answer 12

the center of gravity of the displaced volume of water, equal in shape and volume of the submerged object that is displaced.

Question 13

what does an object needs to have its center of gravity and center of buoyancy to have the same location

Answer 13

to have relatively uniform density

Question 14

where does the center of buoyancy is locateed in a human body

Answer 14

superiorly to the center of gravity.

Question 15

The line of action of gravitational force through the center of gravity will be vertically downward/upward

The line of action of buoyant force through the center of buoyancy will be vertically downward/upward.

Answer 15

downward
upward

Question 16

Dynamic fluid force vector can be resolved into two components:

Answer 16

perpendicular component: lift
vertical component: drag

Question 17

what is the drag force

Answer 17

the parallel component of dynamic fluid force that acts in the opposite direction of system motion with respect to the fluid.

Tends to resist motion of the system through the fluid

Question 18

which force tend to resist motion of the system

Answer 18

drag force

Question 19

The greater the decrease in velocity of the molecules and the faster the rate of this decrease, the greater/smaller the total drag.

Answer 19

greater

Question 20

Drag forces are produced by two different means

Answer 20

surface drag and form drag

Question 21

what is surface drag

Answer 21

Surface drag may be thought of as equivalent to the sum of the friction forces acting between the fluid molecules and the surface of the object.

Question 22

what is form drag

Answer 22

Form drag may be thought of as equivalent to the sum of the impact forces resulting from the collisions between the fluid molecules and the object.

Question 23

what is form drag and how does it vary

Answer 23

due to a relatively higher pressure on the leading edge of the object compared to its trailing edge.
The larger the changes in direction, the larger the forces exerted.
Form drag thus increases as the amount of turbulent flow increases.

Question 24

what is a lift force

Answer 24

the perpendicular component of dynamic fluid force that acts in any direction that is perpendicular to the system motion with respect to the fluid.
Lift tends to change the direction of system motion.

Question 25

which force tend to change the direction of a system in motion

Answer 25

lift

Question 26

T/F A lift force can be directed upward, downward, or in any direction

Answer 26

true

Question 27

The possible directions of the lift force are determined by

Answer 27

the direction of flow of the fluid

Question 28

The possible directions of the lift force are determined by

Answer 28

the direction of flow of the fluid

Question 29

more particule under the object result in what type of lift

Answer 29

upward lift

Question 30

more particule above the object result in what type of lift

Answer 30

downward

Question 31

what is magnus force

Answer 31

lift cause by rotation