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3 years ago

7

The hair dryer has a plastic case so there is no need for an earth wire connection in the plug ,explain why the hair dryer is st

ill safe to use.

1 answer:

AVprozaik [17]3 years ago

8 0

Answer:

plastics are unable to conduct electricity and heat due to there being no free flowing electrons, meaning they are safe to use.

Explanation:

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• A cable is suspended over a pulley. A 5.0 kg mass is attached to

Galina-37 [17]

Answer:

Tension= $\frac{20g}{3}$ (g=acceleration of gravity)

Explanation:

Given that,

A 5Kg and 10Kg are attached by a cable suspended over a pulley.

As 10Kg > 5Kg , the 10 kg mass accelerates down and the 5kg mass accelerates up, let it be a. Let the tension in the cable be T.

So, the equations of motion are

$10g-T = 10a$

$T-5g=5a$

Now adding them we get,

$5g=15a$

$a=\frac{g}{3}$

Substituting them back in the equation we get,

$10g-10(\frac{g}{3} ) = T$

$T= \frac{20g}{3}$

3 0

3 years ago

Carbon is allowed to diffuse through a steel plate 11 mm thick. The concentrations of carbon at the two faces are 0.88 and 0.41

Serhud [2]

Answer:

The temperature is 2584.5 K

Explanation:

Given:

Activation energy $Q = 80000$ $\frac{J}{mol}$

Preexponential $D= 6.2 \times 10^{-7}$ $\frac{m^{2} }{s}$

Diffusion flux $J = 6.4 \times 10^{-10}$ $\frac{kg}{m^{2} s}$

Thickness of plate $\Delta x = 11 \times 10^{-3}$ m

Concentration of carbon at two faces $\Delta C = (0.88 - 0.41 ) = 0.47$ $\frac{kg}{m^{3} }$

From the formula of temperature in terms of diffusion flux,

$T = (\frac{Q}{R} ) \frac{1}{\ln (\frac{D\Delta C}{J\Delta x} )}$

Where $R =$ 8.314 $\frac{J}{mol.K}$ ( gas constant )

Put the values and find the temperature,

$T = (\frac{80000}{8.314} ) \frac{1}{\ln (\frac{6.2 \times 10^{-7} \times 0.47 }{6.4 \times 10^{-10}\times 11 \times 10^{-3} } )}$

$T = 2584.5$ K

Therefore, the temperature is 2584.5 K

8 0

3 years ago

Estimate the force required to bind the two protons in the He nucleus together. (Hint: Model the protons as point charges. Assum

scoray [572]

Answer:

F = 2.30 10⁴ N

Explanation:

The force required to link two gates must be equal to or greater than the electrostatic force of repulsion, because the protons have equal charges.

F = k q₁ q₂ / r²

Where k is the Coulomb constant that is worth 8.99 10⁹ N m² / C²

In this case the proton charge is 1.6 10⁻¹⁹ C and the distance between them is approximately the diameter of the core r = 10⁻¹⁵ m

Let's calculate

F = 8.99 10⁹ (1.6 10⁻¹⁹)² / (10⁻¹⁵)²

F = 2.30 10⁴ N

The bond strength must be equal to or greater than this value

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3 years ago

This is a cell, which is the basic unit of all life. All organs in human bodies are made of cells and require oxygen to survive.

kotegsom [21]

The two systems that work together to deliver oxygen are D, respiratory and cardiovascular

5 0

3 years ago

Help yet again :) A hockey player is skating on the ice at 15km/h. He shoots the puck at 138 km/h according to a radar gun on th

IceJOKER [234]

Answer:

speed of puck acc. to the radar gun = 138 km/h

speed of player = 15 km/h

since the player is in motion when he shoots, the speed of the puck will be the sum of the speed of the player and the speed at which he shot. so,

speed of puck = speed of player + speed of puck acc. to player

138 = 15 + speed of puck acc. to player

speed of puck acc. to player = 138 -15

speed of puck acc. to player = 123 km/h

Brainly this answer if you think it deserves it

7 0

3 years ago