1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
finlep [7]
4 years ago
10

Engineers are trying to create artificial "gravity" in a ringshaped space station by spinning it like a centrifuge. The ring is

171 m in radius. How quickly must the space station turn in order to give the astronauts inside it apparent weights equal to their real weights at the earth's surface? Use g=9.81 m/s2.
Engineering
1 answer:
kotegsom [21]4 years ago
7 0

Answer:

The space station must turn at 0.24 rad/s to give the astronauts inside it apparent weights equal to their real weights at the earth’s surface.

Explanation:

In circular motion there’s always a radial acceleration that points toward the center of the circumference, so because the space station is spinning like a centrifuge it has a radial acceleration towards the center of the trajectory. To imitate the weight of the passengers on earth, they should turn the station in a way that the radial acceleration equals earth gravitational acceleration; this is:

a_{rad}=9.81\frac{m}{s^{2}}\,\,(1)

And radial acceleration is also defined as:

a_{rad}=\frac{v^{2}}{R}\,\,(2)

with v the tangential velocity of the station and R the radius of the ring, solving for v:

v=\sqrt{a_{rad}R}=\sqrt{(9.81)(171)}\simeq40.96\frac{m}{s^{2}}\,\,(3)

We can find the angular velocity using the following equation:

\omega=\frac{v}{R}=\frac{40.96}{171}\simeq0.24\frac{rad}{s}

That is the angular velocity the space station must turn.

You might be interested in
Explain three (3) modes of heat transfer in air conditioning system.
LenKa [72]

Answer:

1. Conduction

2. Convection

3. Radiation

Explanation:

The 3 modes of heat transfer i an air conditioning system:

1. Conduction:

The transfer of heat by conduction  takes place in solid and is when the conduction takes place as a result of direct contact in between the interacting material which transfer the heat energy from particle to particle thus conducting the heat through out the system.

2. Convection:

The other mode for the transfer of heat which takes place especially in fluids - gases and liquids is through the technique of convection in which the transfer of heat takes place by the circular motion of the atoms and molecules of the fluid which carries the heat energy and results in the distribution of the heated fluid in the entire system thus transferring all the heat energy in the entire system.

3. Radiation:

The third mode of heat transfer in the air conditioning system is through radiation. This method transfers the heat by making use of the electro-magnetic radiation in the infra red spectrum where the waves of the spectrum transfers the heat energy with the help of a medium or without any medium at all.

Thus making the radiation method of heat transfer as the only method out of the three methods which does not require the material medium for the transfer of heat energy.

4 0
3 years ago
Indicate the correct statement about the effect of Reynolds number on the character of the flow over an object.
sergeinik [125]

Answer:

If Reynolds number increases the extent of the region around the object that is affected by viscosity decreases.

Explanation:

Reynolds number is an important dimensionless parameter in fluid mechanics.

It is calculated as;

R_e__N} = \frac{\rho vd}{\mu}

where;

ρ is density

v is velocity

d is diameter

μ is viscosity

All these parameters are important in calculating Reynolds number and understanding of fluid flow over an object.

In aerodynamics, the higher the Reynolds number, the lesser the viscosity plays a role in the flow around the airfoil. As Reynolds number increases, the boundary layer gets thinner, which results in a lower drag. Or simply put, if Reynolds number increases the extent of the region around the object that is affected by viscosity decreases.

5 0
3 years ago
What is the metal removal rate when a 2 in-diameter hole 3.5 in deep is drilled in 1020 steel at cutting speed of 120 fpm with a
Studentka2010 [4]

Answer:

a) the metal removal rate is 14.4 in³/min

b) the cutting time is 0.98 min

Explanation:

Given the data from the question

first we find the rpm for the spindle of the drilling tool, using the equation

Ns = 12V/πD

V is the cutting speed(120 fpm) and D is the diameter of the hole( 2 in)

so we substitute

Ns = 12 × 120 / π2

Ns = 1440 / 6.2831

Ns = 229.18 rmp

Now we find the metal removal rate using the equation

MRR = (πD²/4) Fr × Ns

Fr is the feed rate( 0.02 ipr ),

so we substitute

MRR = ((π × 2²)/4) × 0.02 × 229.18

MRR = 14.3998 ≈ 14.4 in³/min

Therefore the metal removal rate is 14.4 in³/min

Next we find the allowance for approach of the tip of the drill

A = D/2

A = 2/2

= 1 in

now find the time required to drill the hole

Tm = (L + A) / (Fr × Ns)

Lis the the depth of the hole( 3.5 in)

so we substitute our values

Tm = (3.5 + 1) / (0.02 × 229.18  )

Tm = 4.5 / 4.5836

Tm = 0.98 min

Therefore the cutting time is 0.98 min

8 0
3 years ago
Which of the following is NOT true about hydraulic valves? A. Directional control valves determine the path of a fluid in a give
Lelechka [254]

Answer: Option D is not true of hydraulic valves. A hydraulic valve is a device that can change the opening degree of liquid flow path

Explanation:

The pilot check valve allows flow of liquid in one direction and blocks flow in the opposite direction

5 0
4 years ago
Question 74
torisob [31]

Answer:

C). rearview mirror (at least of four inches by four inches).

Explanation:

<u>A 'rearview mirror' would be needed in case one is required to pull an individual on water skis after a PWC(personal watercraft) that is rated for carrying two persons only</u>. This wide-angle mirror for rearview would allow the operator to monitor the person who is being towed constantly along with riding the ski at the same time. It is considered illegal to tow a person on a vessel without having a rearview mirror and at the same time, the limited capacity must also be followed strictly. Hence, <u>option C</u> is the correct answer.

7 0
3 years ago
Other questions:
  • The statement that is NOT true about the concept of a boundary layer on an object is: a. the Reynolds number is greater than uni
    6·1 answer
  • Which statement about direct-mail messages is most accurate? Group of answer choices Direct mail is an effective channel for per
    15·1 answer
  • Air is contained in a vertical piston–cylinder assembly such that the piston is in static equilibrium. The atmosphere exerts a p
    9·1 answer
  • Suppose you were a heating engineer and you wished to consider a house as a dynamic system. Without a heater, the average temper
    6·1 answer
  • Which best describes the body in terms of simple machines?
    6·1 answer
  • Quinn’s relatives relayed a story about putting on a headset and seeing a digital world that they could walk around in and explo
    8·2 answers
  • The Eads Bridge, which crosses the Mississippi River near St Louis, Missouri, was one of the first all steel bridges built in th
    8·1 answer
  • Respond with TRUE if the symbol of the valve shown belows
    5·1 answer
  • You installed a new 40 gallon water heater with a 54,000 BTUh burner. The underground water temperature coming into the house is
    9·1 answer
  • Describe how you would control employee exposure to excessive noise in a mining environment
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!