Chapter Four

Question 1

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?

Answer 1

Linear Speed Principle

Question 2

Which of the following describe “a change in factor” that would decrease the time it takes to travel a specific linear distance?

Answer 2

an increase in the body’s linear speed (s)

and/or

a decrease in the distance to be travelled (l)

Question 3

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)?

Answer 3

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

Question 4

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.

Answer 4

First

Question 5

The product of a body’s mass and its linear velocity defines…

Answer 5

Linear Momentum Principle

Question 6

If an athlete increases her velocity, what happens to her linear momentum?

Answer 6

linear momentum increase

Question 7

Linear Conservation of Momentum “requires” which of the following conditions?

Answer 7

no acceleration
constant velocity
balance of factors on object in motion

Question 8

Changes in relative velocity cause changes in all of the following forces except?

Answer 8

buoyant forces

Question 9

Dynamic fluid forces increase the most rapidly when which of the following factors increases.

Answer 9

relative velocity

Question 10

The difference between an object’s velocity and the fluid’s velocity is the definition of…

Answer 10

relative velocity

Question 11

The “dynamic fluid force that opposes motion of the body through a fluid” is the definition of which of the following concepts?

Answer 11

drag force principle

Question 12

Which of the following factors affect the magnitude of the drag force?

Answer 12

fluid density

surface drag

form drag

relative velocity

Question 13

“Drafting” (which reduces the relative velocity) can reduce which of type(s) of force?

Answer 13

drag force

Question 14

“A flow characterized by smooth, parallel layers of fluid” is the definition of which of the following?

Answer 14

laminar flow

Question 15

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?

Answer 15

form drag

Question 16

The two types of fluid motion that influence form drag are…

Answer 16

laminar flow (higher pressure)

and

turbulent flow (lower pressure)

Question 17

The dimples on a golf ball traveling at greater than 20 mph influence drag force by…

Answer 17

form drag

-rougher surface will result in a smaller region of turbulent flow

Question 18

In order to reduce “surface drag,” you should…

Answer 18

wear skin tight clothes

remove body hair

Question 19

Which of the following describe “a change in factor” that would decrease the magnitude of the drag force?

Answer 19

a decrease in:

• form drag
• surface drag
• fluid density
• relative velocity

Question 20

The buoyant force acts in the ______ direction.

Answer 20

upward

Question 21

The buoyant force acting on your body when you are completely submerged under water is determined by knowing…

Answer 21

volume of water displacement, density of water, acceleration due to gravity

Question 22

Which of the following forces always acts in a vertical direction (either positive or negative)?

Answer 22

buoyant force

weight

Question 23

Which of the following statement(s) is/are true regarding the density of fat and muscle tissue?

Answer 23

muscle and bone density is GREATER than 1000kg/m3 (will sink)

fat has a density LESS than 1000 kg/m3 (will float)

Question 24

A submerged object will rise up to the surface if ______.

Answer 24

if the density is less than water

Question 25

The inverse relationship between relative velocity and relative pressure (e.g., higher relative velocity results in lower pressure) in a fluid is called _______ principle.

Answer 25

Bernoulli’s

Question 26

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?

Answer 26

lift force principle

Question 27

Lift can occur in which direction?

Answer 27

lateral or perpendicular to the flow of direction

Question 28

Which of the following methods for creating Lift force would influence the time of flight and the horizontal distance travelled by a ski jumper?

Answer 28

changing the angle of attack

Question 29

Which of the following statement(s) is/are true of the Magnus force?

Answer 29

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”

Question 30

Which of the following forces would affect a spinning ball as it travels through the air?

Answer 30

Magnus Forces

Lift Force
Drag Force

Question 31

Which of the following describe “a change in factor” that would increase the magnitude of the lift force?

Answer 31

AN INCREASE IN:

coefficient of lift

fluid density

surface area/area for lift

relative velocity