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
enyata [817]
3 years ago
15

Which activity promotes the preservation of species

Engineering
1 answer:
miv72 [106K]3 years ago
8 0

Answer:

A

Explanation:

You might be interested in
(a) Differentiate between heat treatment of ferrous and non-ferrous alloys (b) With your understanding of material's thermal pro
liubo4ka [24]

Answer:

In ferrous metal iron present but on the other hand in the non ferrous material iron does not present.That is why there is a different heat treatment process for ferrous and nonferrous materials.

Ferrous materials contains iron is the main constitute.Like steel ,cast iron ,wrought iron .Steel and cast iron are  the alloy element of iron ans carbon.Wrought iron is the purest from of iron.

Heat treatment process for  ferrous materials :

1.Normalizing

2.Annealing

3.Quenching

4.Surface hardening

Heat treatment process for non ferrous materials :

Mostly annealing process is used for non ferrous materials.After annealing non ferrous will become soft.

When two metal plates are joined then they form a bimetallic structure.The bimetallic structure is used to find the relationship of thermal temperature and the mechanical displacement.

The use of bimetallic structure -In clock ,thermometers ,engines.

7 0
3 years ago
A system that is not influence anyway by the surroundings is called a)- control mass system b)- Isothermal system c)-- isolated
NARA [144]

Answer:

Isolated system

Explanation:

By definition of a closed system it means that a system that does not interact with it's surroundings in any manner

The other options are explained as under:

Isothermal system : It is a system that does not allow it's temperature to change

Control Mass system : It is a system whose mass remains conserved which means the mass entering the system equals the mass leaving the system

Open system: It is a system that allows transfer of mass and energy across it's boundary without any opposition i.e freely.

5 0
3 years ago
An excited electron in an Na atom emits radiation at a wavelength 589 nm and returns to the ground state. If the mean time for t
11Alexandr11 [23.1K]

Answer:   Inherent width in the emission line: 9.20 × 10⁻¹⁵ m or 9.20 fm

                length of the photon emitted: 6.0 m

Explanation:

The emitted wavelength is 589 nm and the transition time is ∆t = 20 ns.

Recall the Heisenberg's uncertainty principle:-

                                 ∆t∆E ≈ h ( Planck's Constant)

The transition time ∆t corresponds to the energy that is ∆E

E=h/t = \frac{(1/2\pi)*6.626*10x^{-34} J.s}{20*10x^{-9} } = 5.273*10x^{-27} J =  3.29* 10^{-8} eV.

The corresponding uncertainty in the emitted frequency ∆v is:

∆v= ∆E/h = (5.273*10^-27 J)/(6.626*10^ J.s)=  7.958 × 10^6 s^-1

To find the corresponding spread in wavelength and hence the line width ∆λ, we can differentiate

                                                    λ = c/v

                                                    dλ/dv = -c/v² = -λ²/c

Therefore,

      ∆λ = (λ²/c)*(∆v) = {(589*10⁻⁹ m)²/(3.0*10⁸ m/s)} * (7.958*10⁶ s⁻¹)

                                 =  9.20 × 10⁻¹⁵ m or 9.20 fm

     The length of the photon (<em>l)</em> is

l = (light velocity) × (emission duration)

  = (3.0 × 10⁸  m/s)(20 × 10⁻⁹ s) = 6.0 m          

                                                   

6 0
3 years ago
When something is plumb, it is
GrogVix [38]

Answer:

  C. exactly vertical

Explanation:

"Plumb" means "exactly vertical."

5 0
3 years ago
Read 2 more answers
A cannon ball is fired with an arching trajectory such that at the highest point of the trajectory the cannon ball is traveling
ELEN [110]

Answer:

The radius of curvature is 979 meter

Explanation:

We have given velocity of the canon ball v = 98 m/sec

Acceleration due to gravity g=9.81m/sec^2

We know that at highest point of trajectory angular acceleration is equal to acceleration due to gravity

Acceleration due to gravity is given by a_c=\frac{v^2}{r}, here v is velocity and r is radius of curvature

So \frac{98^2}{r}=9.81

r = 979 meter

So the radius of curvature is 979 meter

8 0
4 years ago
Other questions:
  • A heat pump with an ideal compressor operates between 0.2 MPa and 1 MPa. Refrigerant R134a flows through the system at a rate of
    15·1 answer
  • Water is flowing into the top of an open cylindrical tank (which has a diameter D) at a volume flow rate of Qi and the water flo
    15·2 answers
  • Practice Problem: True Stress and Strain A cylindrical specimen of a metal alloy 49.9 mm long and 9.72 mm in diameter is stresse
    13·1 answer
  • Name the seven physical qualities for which standards have been developed.
    7·1 answer
  • I WILL GIVE 20 POINTS!!
    11·2 answers
  • A piece of aluminum wire is 500 ft long and has a diameter of 0.03 inches. What is the resistance of the piece of wire?​
    6·1 answer
  • The drag coefficient of a car at the design conditions of 1 atm, 25°C, and 90 km/h is to be determined experimentally in a large
    8·1 answer
  • A solid cylindrical workpiece made of 304 stainless steel is 150 mm in diameter and 100 mm is high. It is reduced in height by 5
    12·1 answer
  • Refrigerant 134a enters the evaporator of a refrigeration system operating at steady state at -16oC and a quality of 20% at a ve
    13·1 answer
  • Which explanation best summarizes what went wrong during Paul’s cost analysis?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!