Question 1

To set the world land speed record and travel faster than the speed of sound, the Thrust SSC vehicle used two jet engines that produced about a 250,000 horsepower. The principal reason why this car needed so much power to travel so fast is that

Accepted Answer

A)   a car's momentum is proportional to its power, so reaching very high momentum requires very high power.
B)   the pressure drag on a car increases dramatically as the car's speed increases.
C)   the force of the car's momentum was enormous and the jet engines were needed to supply that force.
D)   Newton's second law requires a very fast moving object to have a very large acceleration and thus a very large force.

Question 2

Suppose you are practicing baseball and throw the ball with a spin so that it moves forward and curves to the right. Now when the actual game takes place you are pitching with the wind behind you. Please explain how you could alter your throw so as to make the ball take the same path.

Accepted Answer

Drag resistance is responsible for slowi...

Question 3

As you know, dimples on golf balls and fuzz on tennis balls are helpful because that gives the objects longer range. Please explain why implementing the same design for airplane wings is not a good thing.

Accepted Answer

Dimples on golf balls and fuzz on tennis...

Question 4

You are at a truck stop and overhear some young physics professors talking about drag, and in particular how large trucks don't experience much drag because they can coast far but something like a piece of paper has a lot of drag. What could you add to their discussion to make it more accurate?

Accepted Answer

I would add that drag is large the faste...

Question 5

The diameter of a pipe is tripled while the pressure difference across the pipe remains the same. The volume flow rate of the pipe increases by a factor of

Accepted Answer

A)   3
B)   9
C)   27
D)   81

Question 6

As the Reynolds number decreases,

Accepted Answer

A)   flow is becoming more laminar.
B)   flow is going from being viscous dominated to inertia dominated and therefore turbulent.
C)   flow is slowing down.
D)   flow is speeding up.

Question 7

Suppose you are a teacher and, to your excitement, the local weather person comes for a classroom visit! She is talking about tornadoes and says that there is air moving very rapidly upwards through the funnel but air standing basically still outside the funnel. Such motion would cause

Accepted Answer

A)   high pressure inside the funnel.
B)   low pressure inside the funnel.
C)   the funnel pressure to be equal to the pressure outside.
D)   houses on the ground to implode.

Question 8

The top surface of a calm, smoothly flowing stream is always at atmospheric pressure. As water in this stream runs into a tree stump and slows almost to a stop, the water's top surface

Accepted Answer

A)   shifts upward slightly above the normal stream level.
B)   shifts downward slightly below the normal stream level.
C)   stays at the same height and does not begin to rotate.
D)   stays at the same height but begins to rotate clockwise as viewed from above.

Question 9

In some motion pictures, airplane passengers are sucked out of the plane when a door is opened and the airplane is in flight. Comment on whether such an effect is scientifically realistic or not.

Accepted Answer

The airplane is moving very rapidly thro...

Question 10

A stream of smoothly flowing water arcs through the air and hits the side window of a house. At the surface of the window, right where the stream of water hits it, the water's pressure is

Accepted Answer

A)   lower than atmospheric and the water's speed is faster than in the stream.
B)   higher than atmospheric and the water's speed is faster than in the stream.
C)   higher than atmospheric and the water's speed is slower than in the stream.
D)   lower than atmospheric and the water's speed is slower than in the stream.

Question 11

Consider a baseball thrown to the left, spinning clockwise and experiencing laminar flow as shown in the picture below. Based upon the wind speed pattern shown, comment on whether or not this would account for the ball's obtaining drag. Also, mention whether the ball shown is a good candidate for the Magnus force or for wake deflection.

Accepted Answer

Yes it does explain drag based on the di...

Question 12

The pressure in a water pipe is always lower in regions where the water moves faster only when

Accepted Answer

A)   the pipe increases in altitude towards the faster fluid end
B)   the pipe is level.
C)   anything other than water is in the pipe
D)   the pipe is made of plastic

Question 13

Please consider the funnel of a tornado which holds its size (radius) and therefore its rotation rate. Now imagine that the funnel is made up of many tiny particles moving around in circles. You are examining one of those particles, which represents a tiny portion of the funnel cloud. You may ignore gravity for this problem.
-Please identify the direction of the net force acting on one of the particles.

Accepted Answer

Since the small piece is rotat...

Question 14

You construct a water-powered go-cart by attaching a large tank of water to a cart. The water can be forced out a nozzle by connecting a tank of high-pressure air to the water tank. In preparation for your first ride, you position this contraption facing away from a brick wall. You climb on and start spraying the water against the wall. To your delight you accelerate away from the wall and begin to move. When you have moved far enough away from the wall that the stream of water can no longer hit it, you

Accepted Answer

A)   continue to accelerate as the water sprays out the back of the cart.
B)   continue to move, but stop accelerating since the water can no longer push against the wall.
C)   feel lighter than normal since the water hitting the ground will produce an upward force.
D)   continue to accelerate, but less since it takes more force to accelerate a moving object than a stationary one.

Question 15

You have just set up a weather station for your daughter to observe wind speeds at home. You had to move it up from the ground because when it was too close to the ground the wind speed readings are all too small. This is because

Accepted Answer

A)   The air near the ground is too dense to move well.
B)   The ground is hot so air movement there is always upward, never sideways.
C)   The boundary layer of a moving fluid moves slower than at other points farther into the fluid.
D)   Someone kept stepping on the wind speed gauge.

Question 16

Fluids have viscosity because

Accepted Answer

A)   the atoms and molecules within the fluid interact with each other, producing internal frictional forces.
B)   the atoms and molecules within the fluid are heavy and hard to push..
C)   molecules in fluids are long and get tangled.
D)   they are always in contact with some boundary.

Question 17

A typical cruising speed for a jet is

Accepted Answer

A)   24,000 km/h
B)   800 km/h
C)   100 km/h
D)   800 km/sec

Question 18

Honey is about _______ times more viscous than air.

Accepted Answer

A)   10
B)   1,000
C)   1,000,000
D)   10,000,000

Question 19

You are filling a jar of honey from the spigot at the bottom of a large barrel at the grocery store. The honey flows extremely slowly, so the store manager has the barrel refilled. Now the honey flows much more rapidly from the spigot because

Accepted Answer

A)   the pressure of the honey at the bottom of the barrel increases as the height of honey in the barrel increases.
B)   the density of the honey decreases as the height of the honey in the barrel increases.
C)   the viscosity of the honey decreases as the height of honey in the barrel increases.
D)   the viscosity of the honey increases as the height of honey in the barrel increases.

Question 20

One of the many things that make an artery blockage dangerous is

Accepted Answer

A)   The amount of fluid passing through the blockage is proportional to the square of the diameter of the opening.
B)   The amount of fluid passing through the blockage is proportional to the fourth power of the diameter of the opening.
C)   The amount of fluid passing through the blockage is proportional to the area of the opening.
D)   The amount of fluid passing through the blockage is proportional to the diameter of the opening.

Exam 6: Fluids and Motion

Correct Answer
verified
Yes it does explain drag based on the di...
View Answer

You are filling a jar of honey from the spigot at the bottom of a large barrel at the grocery store. The honey flows extremely slowly, so the store manager has the barrel refilled. Now the honey flows much more rapidly from the spigot because

Correct Answer
verified

Suppose you are a teacher and, to your excitement, the local weather person comes for a classroom visit! She is talking about tornadoes and says that there is air moving very rapidly upwards through the funnel but air standing basically still outside the funnel. Such motion would cause

Correct Answer
verified

You have just set up a weather station for your daughter to observe wind speeds at home. You had to move it up from the ground because when it was too close to the ground the wind speed readings are all too small. This is because

Correct Answer
verified

Fluids have viscosity because

Correct Answer
verified

One of the many things that make an artery blockage dangerous is

Correct Answer
verified

A stream of smoothly flowing water arcs through the air and hits the side window of a house. At the surface of the window, right where the stream of water hits it, the water's pressure is

Correct Answer
verified

A typical cruising speed for a jet is

Correct Answer
verified

The top surface of a calm, smoothly flowing stream is always at atmospheric pressure. As water in this stream runs into a tree stump and slows almost to a stop, the water's top surface

Correct Answer
verified

You are at a truck stop and overhear some young physics professors talking about drag, and in particular how large trucks don't experience much drag because they can coast far but something like a piece of paper has a lot of drag. What could you add to their discussion to make it more accurate?

Correct Answer
verified
I would add that drag is large the faste...
View Answer

As you know, dimples on golf balls and fuzz on tennis balls are helpful because that gives the objects longer range. Please explain why implementing the same design for airplane wings is not a good thing.

Correct Answer
verified
Dimples on golf balls and fuzz on tennis...
View Answer

Correct Answer
verified

Honey is about _______ times more viscous than air.

Correct Answer
verified

Correct Answer
verified
Since the small piece is rotat...
View Answer

The diameter of a pipe is tripled while the pressure difference across the pipe remains the same. The volume flow rate of the pipe increases by a factor of

Correct Answer
verified

In some motion pictures, airplane passengers are sucked out of the plane when a door is opened and the airplane is in flight. Comment on whether such an effect is scientifically realistic or not.

Correct Answer
verified
The airplane is moving very rapidly thro...
View Answer

To set the world land speed record and travel faster than the speed of sound, the Thrust SSC vehicle used two jet engines that produced about a 250,000 horsepower. The principal reason why this car needed so much power to travel so fast is that

Correct Answer
verified

As the Reynolds number decreases,

Correct Answer
verified

The pressure in a water pipe is always lower in regions where the water moves faster only when

Correct Answer
verified

Suppose you are practicing baseball and throw the ball with a spin so that it moves forward and curves to the right. Now when the actual game takes place you are pitching with the wind behind you. Please explain how you could alter your throw so as to make the ball take the same path.

Correct Answer
verified
Drag resistance is responsible for slowi...
View Answer

Exam 6: Fluids and Motion

Correct AnswerverifiedYes it does explain drag based on the di...View AnswerShow Answer

You are filling a jar of honey from the spigot at the bottom of a large barrel at the grocery store. The honey flows extremely slowly, so the store manager has the barrel refilled. Now the honey flows much more rapidly from the spigot because

Correct AnswerverifiedShow Answer

Suppose you are a teacher and, to your excitement, the local weather person comes for a classroom visit! She is talking about tornadoes and says that there is air moving very rapidly upwards through the funnel but air standing basically still outside the funnel. Such motion would cause

Correct AnswerverifiedShow Answer

You have just set up a weather station for your daughter to observe wind speeds at home. You had to move it up from the ground because when it was too close to the ground the wind speed readings are all too small. This is because

Correct AnswerverifiedShow Answer

Fluids have viscosity because

Correct AnswerverifiedShow Answer

One of the many things that make an artery blockage dangerous is

Correct AnswerverifiedShow Answer

A stream of smoothly flowing water arcs through the air and hits the side window of a house. At the surface of the window, right where the stream of water hits it, the water's pressure is

Correct AnswerverifiedShow Answer

A typical cruising speed for a jet is

Correct AnswerverifiedShow Answer

The top surface of a calm, smoothly flowing stream is always at atmospheric pressure. As water in this stream runs into a tree stump and slows almost to a stop, the water's top surface

Correct AnswerverifiedShow Answer

You are at a truck stop and overhear some young physics professors talking about drag, and in particular how large trucks don't experience much drag because they can coast far but something like a piece of paper has a lot of drag. What could you add to their discussion to make it more accurate?

Correct AnswerverifiedI would add that drag is large the faste...View AnswerShow Answer

As you know, dimples on golf balls and fuzz on tennis balls are helpful because that gives the objects longer range. Please explain why implementing the same design for airplane wings is not a good thing.

Correct AnswerverifiedDimples on golf balls and fuzz on tennis...View AnswerShow Answer

Correct AnswerverifiedShow Answer

Honey is about _______ times more viscous than air.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedSince the small piece is rotat...View AnswerShow Answer

The diameter of a pipe is tripled while the pressure difference across the pipe remains the same. The volume flow rate of the pipe increases by a factor of

Correct AnswerverifiedShow Answer

In some motion pictures, airplane passengers are sucked out of the plane when a door is opened and the airplane is in flight. Comment on whether such an effect is scientifically realistic or not.

Correct AnswerverifiedThe airplane is moving very rapidly thro...View AnswerShow Answer

To set the world land speed record and travel faster than the speed of sound, the Thrust SSC vehicle used two jet engines that produced about a 250,000 horsepower. The principal reason why this car needed so much power to travel so fast is that

Correct AnswerverifiedShow Answer

As the Reynolds number decreases,

Correct AnswerverifiedShow Answer

The pressure in a water pipe is always lower in regions where the water moves faster only when

Correct AnswerverifiedShow Answer

Suppose you are practicing baseball and throw the ball with a spin so that it moves forward and curves to the right. Now when the actual game takes place you are pitching with the wind behind you. Please explain how you could alter your throw so as to make the ball take the same path.

Correct AnswerverifiedDrag resistance is responsible for slowi...View AnswerShow Answer

Correct Answer
verified
Yes it does explain drag based on the di...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
I would add that drag is large the faste...
View Answer

Correct Answer
verified
Dimples on golf balls and fuzz on tennis...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Since the small piece is rotat...
View Answer

Correct Answer
verified

Correct Answer
verified
The airplane is moving very rapidly thro...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Drag resistance is responsible for slowi...
View Answer