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dybincka [34]
3 years ago
8

RACTIC PTUDIES

Physics
1 answer:
Amanda [17]3 years ago
6 0

Answer:

The illumination on the book before the lamp is moved is 9 times the illumination after the lamp is moved.

Explanation:

The distance of the book before the lamp is moved, d_{b} = 30 cm

The distance of the book after the lamp is moved, d_{a} = 90 cm

Illumination can be given by the formula, E = \frac{P}{4 \pi d^{2} }

Illumination before the lamp is moved, E_{b} = \frac{P}{4 \pi d_{b} ^{2} }

Illumination after the lamp is moved, E_{a} = \frac{P}{4 \pi d_{a} ^{2} }

\frac{E_{a}}{E_{b}} } = \frac{\frac{P}{4 \pi d_{a} ^{2} } }{\frac{P}{4 \pi d_{b} ^{2} } }

\frac{E_{a} }{E_{b} } = \frac{d_{b} ^{2} }{d_{a} ^{2}} \\\frac{E_{a} }{E_{b} } = \frac{30^{2} }{90 ^{2}}\\\frac{E_{a} }{E_{b} } =\frac{900 }{8100}\\\frac{E_{a} }{E_{b} } =\frac{1 }{9}

E_{b} = 9E_{a}

The illumination on the book before the lamp is moved is 9 times the illumination after the lamp is moved.

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While traveling along a highway a driver slows from 32 m/s and comes to a stop with an acceleration of -6 m/s2. How long did it
diamong [38]

Answer: 6s

Explanation:

Vs=32m/s  speed at beginning of slowing down

Vf=0m/s     stop speed

a= -6 m/s²  acceleration

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Use equation for acceleration :

a=(Vf-Vs)/t

a*t=Vf-Vs

t=(Vf-Vs)/a

t=(0-36)/-6

t=-36/-6

t=6 s

7 0
2 years ago
An element is highly conductive, highly reactive, soft, and lustrous. The element most likely belongs to which group?(1 point)
UkoKoshka [18]

An element which is highly conductive, highly reactive, soft, and lustrous is most likely an alkali metal.

Alkali metals are in group 1 of the Periodic table which means that they have only a single valence electron.

This causes them to be soft and highly reactive because:

  • The single valance electron leads to weak bonds amongst the element's atoms which makes them soft
  • The elements want to lose the single valance electron so as to become stable so they will react with other elements to give away the electron.

Examples of alkali electrons include:

  • Lithium
  • Sodium
  • Potassium etc

In conclusion therefore, alkali metals are highly reactive and soft and so the element described above is most likely an alkali metal.

<em>Find out more at brainly.com/question/18722874.</em>

6 0
2 years ago
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what is the transfer of heat energy by direct contact. A . convection b. radiation c. thermal or heat and d. conduction ​
katrin2010 [14]

Answer:

d. conduction ​

Explanation:

Conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.

In the process of heat conduction, thermal energy is usually transferred from fast moving particles to slow moving particles during the collision of these particles. Also, thermal energy is typically transferred between objects that has different degrees of temperature and materials (particles) that are directly in contact with each other but differ in their ability to accept or give up electrons.

Any material or object that allow the conduction (transfer) of electric charge or thermal energy is generally referred to as a conductor. Conductors include metal, steel, aluminum, copper, frying pan, pot, spoon etc.

In conclusion, conduction typically involves the transfer of heat energy by direct contact between two or more conductors such as a pot and electric cooker.

6 0
2 years ago
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If C is 1kg and D is 100kg, and the initial velocities of both balls are 5m/s, how would the magnitude of the forces exerted by
kupik [55]

Answer:

Explanation:

The forces exerted by each mass is best understood in terms of their momentum.

Momentum is a sort of compelling force or impulse. It is given as:

                  Momentum  =  mass x velocity

Let us consider the momentum of the balls;

Substance C;

    Mass  = 1kg

     Velocity  = 5m/s

    Momentum of C = 1 x 5  = 5kgm/s

Substance D:

      Mass  = 100kg

      Velocity  = 5m/s

     Momentum of D  = 100kg x 5m/s  = 500kgm/s

Body D has a higher momentum compared to Body C. This suggests that body D will exert a higher force than C when they collide.

The higher the momentum, the more the force of impact it has.

3 0
3 years ago
A bottle of soda always has a space between the cape and the top of the liquid. Explain<br>​
serious [3.7K]

Answer:

All soft drinks contain water. When soft drink bottles are chilled in sub-zero temperatures, the water on account of its anomalous expansion expands. Thus, to provide space for expanding water, soft drink bottles are not completely filled as otherwise they will burst.

Explanation:

6 0
2 years ago
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