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Luba_88 [7]
3 years ago
7

A garage door opener has a component that stop the door from coming down if something is in the way. This component is made up o

f a laser light on one side and a receiver on the other. Which best explains why this component works.
A) The receiver collects the laser light indicating that something is in the way.

B) Any object blocking the path of the laser will reflect the beam into the reciever.

C) Any object in its path changes the color of the laser before it gets to the reciever.

D) The laser light travels in a straight line towards the receiver, an object in the way blocks this straight line path.


The wavelength of a sound will give us information about________________.
A) how loud the sound will be
B) what produced the sound
C) the high or low pitch of the sound
D) the speed of sound

Which statement about how sound travels is true?
A) The speed of sound is the same at all times.
B) The speed of sound depends on the material it travels through.
C) Sound vibrations only move through a vacuum.
D) Sound moves faster through insulators than conductors.

Which statement about the electromagnetic spectrum is false?
A) There are wavelengths other than those of visible light in the spectrum.
B) Microwaves have a longer wavelength than visible light.
C) The higher the energy of the wavelength, the more dangerous they are.
D) Infrared light waves are visible.
Physics
1 answer:
Olin [163]3 years ago
4 0

laser in the garage . . . D

wavelength of a sound . . . C

how sound travels . . . B

electromagnetic spectrum . . . D

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A 0.03-kg bullet is fired with a horizontal velocity of 470 m/s and becomes embedded in block B which has a mass of 3 kg. After
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Answer with Explanation:

We are given that

Mass of bullet,m_1=0.03 kg

u_1=470 m/s

m_2=3 kg

\mu_k=0.2

m_3=30 kg

We have to find the velocity of the bullet and block B after the first impact and final velocity of the carrier.

According to law of conservation of momentum

m_1u_1=(m_1+m_2)v

0.03(470)=(0.03+3)v

v=\frac{0.03(470)}{(0.03+3)}=4.65 m/s

Hence, the velocity of the bullet and block B after the first impact=4.65 m/s

According to law of conservation of momentum

(m_1+m_2)v=(m_1+m_2+m_3)V

(0.03+3)\times 4.65=(0.03+3+30)V

V=\frac{(0.03+3)\times 4.65}{(0.03+3+30)}

V=0.43 m/s

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4 years ago
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Wood has chemical energy, which can be used to generate thermal and radiant energy when burned in a fireplace. Which best explai
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Answer:

C

Explanation: i took the test

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The following represents a process used to assemble a chair with an upholstered seat. stationsa, b, and c make the seat; station
Mekhanik [1.2K]

There are three questions here:


A. The possible daily output of this process if there is 8 processing time each day?


the time it takes to assemble a chair in seconds = A + B + C + J + K + L + X + Y + Z  

which is equal to = 38 + 34 + 35 + 32 + 30 + 34 + 22 + 18 + 20 =263 per chair



Processing hours = 8 hours x 60 minutes x 60 seconds

= 8 x 60 x 60


= 480 x 60 = 28,800 seconds is available in an 8 hr day.



28,800 / 263 =109.5057034220532


Therefore, It is possible to make 109 chairs in an 8 hour day.



B. Given your output rate in above, what is the efficiency of the process?


The time it takes to assemble a chair in seconds = A+ B + C + J + K + L + X + Y + Z.


= 34 + 34 + 34 + 30 + 30 + 30 + 22 + 18 + 20 = 252.6315789473684 per chair


A total of 252 per chair


Processing hours = 8 hours x 60 minutes x 60 seconds


= 8 x 60 x 60


= 480 x 60 = 28,800 seconds is available in an 8 hour day


= 28,000 / 252 = 114.2857142857143114 chairs


= 109/114 x 100 = 95.6140350877193


Therefore, the efficiency of making the chair is 95.61%


C. What is the flow time of the process?


Flow time is the period that it takes a completed chair to flow through the process from the beginning assemblage step to the last step. Take note that ABC and JKL are parallel legs in the process, and as a result both do not include to flow time to the procedure. In addition, Flow time comprises both pass time and run time at each position in the procedure.

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What is the equation linking pressure difference, depth, density and g
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Pressure difference = depth x density x gravity
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What’s the difference between fiber optic cable, twisted pair cable and coaxial cable?
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Nowadays, two types of fiber optic cables are widely adopted in the field of data transfer—single-mode fiber optic cables and multimode fiber optic cables. A single-mode optical fiber is a fiber that has a small core, and only allows one mode of light to propagate at a time. So it is generally adapted to high speed, long-distance applications. While a multimode optical fiber is a type of optical fiber with a core diameter larger than the wavelength of light transmitted and it is designed to carry multiple light rays, or modes at the same time. It is mostly used for communication over short distances because of its high capacity and reliability, serving as a backbone applications in buildings.

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3 years ago
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