Chapter Four Flashcards
The “linear distance traveled divided by the time it takes to travel a specific linear distance” is the definition of which of the following concepts?
Linear Speed Principle
Which of the following describe “a change in factor” that would decrease the time it takes to travel a specific linear distance?
an increase in the body’s linear speed (s)
and/or
a decrease in the distance to be travelled (l)
Which of the following is/are examples of situations where the type of analysis used to study the activity is based on Newton’s 1st law (i.e., no acceleration)?
movements that involve no change in motion - for example, ice skating
- no net external force
- a body that is moving will continue to move in the same direction with the same speed
- a body at rest will stay at rest
A skater gliding on ice will continue to move in the same direction, with the same speed and with no acceleration. This statement would be an example of Newton’s _______ Law.
First
The product of a body’s mass and its linear velocity defines…
Linear Momentum Principle
If an athlete increases her velocity, what happens to her linear momentum?
linear momentum increase
Linear Conservation of Momentum “requires” which of the following conditions?
no acceleration
constant velocity
balance of factors on object in motion
Changes in relative velocity cause changes in all of the following forces except?
buoyant forces
Dynamic fluid forces increase the most rapidly when which of the following factors increases.
relative velocity
The difference between an object’s velocity and the fluid’s velocity is the definition of…
relative velocity
The “dynamic fluid force that opposes motion of the body through a fluid” is the definition of which of the following concepts?
drag force principle
Which of the following factors affect the magnitude of the drag force?
fluid density
surface drag
form drag
relative velocity
“Drafting” (which reduces the relative velocity) can reduce which of type(s) of force?
drag force
“A flow characterized by smooth, parallel layers of fluid” is the definition of which of the following?
laminar flow
Which of the following is the name of the force that is created by a pressure differential between the front and back of a body moving through a fluid?
form drag
The two types of fluid motion that influence form drag are…
laminar flow (higher pressure)
and
turbulent flow (lower pressure)
The dimples on a golf ball traveling at greater than 20 mph influence drag force by…
form drag
-rougher surface will result in a smaller region of turbulent flow
In order to reduce “surface drag,” you should…
wear skin tight clothes
remove body hair
Which of the following describe “a change in factor” that would decrease the magnitude of the drag force?
a decrease in:
- form drag
- surface drag
- fluid density
- relative velocity
The buoyant force acts in the ______ direction.
upward
The buoyant force acting on your body when you are completely submerged under water is determined by knowing…
volume of water displacement, density of water, acceleration due to gravity
Which of the following forces always acts in a vertical direction (either positive or negative)?
buoyant force
weight
Which of the following statement(s) is/are true regarding the density of fat and muscle tissue?
muscle and bone density is GREATER than 1000kg/m3 (will sink)
fat has a density LESS than 1000 kg/m3 (will float)
A submerged object will rise up to the surface if ______.
if the density is less than water
The inverse relationship between relative velocity and relative pressure (e.g., higher relative velocity results in lower pressure) in a fluid is called _______ principle.
Bernoulli’s
The “dynamic fluid force that acts in a direction perpendicular to the motion of the body through a fluid” is the definition of which of the following concepts?
lift force principle
Lift can occur in which direction?
lateral or perpendicular to the flow of direction
Which of the following methods for creating Lift force would influence the time of flight and the horizontal distance travelled by a ski jumper?
changing the angle of attack
Which of the following statement(s) is/are true of the Magnus force?
when molecules strike the LOWER surface of the ball, they DON’T slow down as much
when molecules strike the TOP surface of the ball, they are slowed down MORE
“According to Bernoulli’s Principle, then, less pressure will be exerted by the faster moving molecules on the bottom surface of the ball”
Which of the following forces would affect a spinning ball as it travels through the air?
Magnus Forces
Lift Force
Drag Force
Which of the following describe “a change in factor” that would increase the magnitude of the lift force?
AN INCREASE IN:
coefficient of lift
fluid density
surface area/area for lift
relative velocity
