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
Darina [25.2K]
3 years ago
12

Which of the following is a physical change

Physics
2 answers:
Oduvanchick [21]3 years ago
5 0

A physical change would be A. Sawing a piece of wood in half because it's still the same. It would be a chemical reaction if the color of the wood would've changed.

pickupchik [31]3 years ago
4 0

Answer:-

  • <u>Sawing of piece of wood in half.</u>

→ Physical; it is because no chemical properties are changed. They are same, just change is seen physically.

  • <u>Burning</u><u> </u><u>of</u><u> </u><u>a</u><u> </u><u>piece</u><u> </u><u>of</u><u> </u><u>wood</u><u>.</u>

→ Chemical; it is because chemical changes are observed. Wood is converted into Carbon.

  • <u>Rust forming on an iron fence.</u>

→ Chemical; iron looses it's chemical properties on rusting. Thus, it is a chemical change.

  • <u>A copper roof changing color from red to green.</u>

→ Chemical; chemical change is observed.

Conclusion: <em>Sawing a piece of wood in half</em> is the answer.

You might be interested in
A professor's office door is 0.91 m wide, 2.0 m high, and 4.0 cm thick; has a mass of 25 kg; and pivots on frictionless hinges.
olasank [31]

Answer:

F= 5.71 N

Explanation:

width of door= 0.91 m

door closer torque on door= 5.2 Nm

In order to hold the door in open position we need to exert an equal and opposite torque, to the door closer torque, on the door.

so wee need to exert 5.2 Nm torque on the door.

If we want to apply minimum force to exert the required torque we need to apply force perpendicularly on the door knob (end of door) so that to to greater moment arm.

T= r x F

T= r F sin∅

F= T/ (r * sin∅)

F= 5.2/ (0.91 * 1)

F= 5.71 N

5 0
3 years ago
How would you respond to a person who argued that the Big Bang theory is incorrect because it is only a theory and theories have
Umnica [9.8K]

Well, you would reply that that's not what theories are. Theories explain the how and the why, laws explain the what. So, the Big Bang theory isn't "just a theory". It's a theory, it explains the how. (Also, if someone tells you it's anti-God or whatever, tell them the thoery was created by a Catholic scientist. True fact.) I hoped this helped!!! (You don't have the include who created the theory if this is for homework.)

5 0
3 years ago
Read 2 more answers
An electron moves in the plane of this screen toward the top of the screen. A magnetic field is also in the plane of the screen
Ad libitum [116K]

Answer: the direction of the magnetic force on the electron will be moving out of the screen, perpendicular to the magnetic field.

Explanation:

The magnetic force F on a moving electron at right angle to a magnetic field is given by the formula:

F = BqVSinØ

If an electron moves in the plane of this screen toward the top of the screen. A magnetic field is also in the plane of the screen and directed toward the right. Then, the direction of the magnetic force on the electron will be perpendicular to the magnetic field

According to the Fleming's left - hand rule, the direction of the magnetic force on the electron will be moving out of the plane of the screen.

6 0
3 years ago
A ball is dropped from the top of the building.it initially moves at 4.0 m/s after 0.5 seconds it moves at 3.8m/s what force is
Ivahew [28]

The correct answer is

Air resistance

In fact, when a ball is in free fall, there are two forces acting on it:

- its weight (force of gravity), acting downward

- the air resistance, acting upward

The effect of the weight is to accelerate the ball, because its direction is the same as the direction of motion of the ball, while the effect of the air resistance is to slow down the ball, because its direction is opposite to that of the motion.

6 0
3 years ago
One of the main factors driving improvements in the cost and complexity of integrated circuits (ICs) is improvements in photolit
nika2105 [10]

Answer:

0.000003782 m

0.000001891 m

0.000001197125 m

Explanation:

\lambda = Wavelength = 248 nm

D = Diameter of beam = 1 cm

f = Focal length = 0.625 cm

The angle is given by

\theta=\dfrac{1.22\lambda}{D}

The width is given by

d=2\theta f\\\Rightarrow d=2\dfrac{1.22\lambda f}{D}\\\Rightarrow d=2\dfrac{1.22\times 248\times 10^{-9}\times 6.25\times 10^{-2}}{1\times 10^{-2}}\\\Rightarrow d=0.000003782\ m

The required width is 0.000003782 m

Minimum resolvable line separation is given by

\dfrac{0.000003782}{2}=0.000001891\ m

The minimum resolvable line separation between adjacent lines is 0.000001891 m

when \lambda=157\ nm

d=2\dfrac{1.22\times 157\times 10^{-9}\times 6.25\times 10^{-2}}{1\times 10^{-2}}\\\Rightarrow d=0.00000239425\ m

The new minimum resolvable line separation between adjacent lines is

\dfrac{0.00000239425}{2}=0.000001197125\ m

6 0
3 years ago
Other questions:
  • Potential difference is measured in units called
    7·2 answers
  • The element chlorine has two naturally occurring isotopes. About 75% of chlorine isotopes are Cl-35 and about 25% are Cl-37.
    12·2 answers
  • PLEASE HELP
    9·2 answers
  • A ball of mass m = 4.6 kg, at one end of a string of length L= 6.6 m, rotates in a vertical circle just fast enough to prevent t
    11·1 answer
  • The following is current scientific evidence supporting the nebular theory on the formation of the solar system. the composition
    9·2 answers
  • What is the de Broglie wavelength for a proton with energy 50 keV? Due to the limitations of Canvas, please give the wavelength
    10·1 answer
  • Unlike addition polymers, condensation polymers form from _____.
    8·2 answers
  • So this helicopter pilot dropped me in the middle of an absolutely smooth frictionless
    10·2 answers
  • what do you think is the purpose of a periscope? Are there any other uses for periscopes besides for submarines?
    6·1 answer
  • A 400 g ball swings in a vertical cirde at the end of
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!