I need help on 7 &8

In a thermostat, what property of the bimetallic coil allows it to contract and expand? The two metals absorb different amounts

Reika [66]

Hello!

In a thermostat, the property of the bimetallic coil that allows it to contract and expand is that The two metals absorb different amounts of thermal energy.

This bimetallic coil is used to transform thermal energy into mechanical movement. Two metals with different thermal expansivity are joined together parallelly and the changes of temperature cause bending in different directions depending on if the temperature is rising or descending.

The differences in the thermal energy absorption of the two metals are the basis for the mechanism of this device.

3 0

3 years ago

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Many industries are powered via distant power stations. Calculate the current flowing through a 7,300m long 10. copper power lin

Oliga [24]

Answer:

Current, I = 1000 A

Explanation:

It is given that,

Length of the copper wire, l = 7300 m

Resistance of copper line, R = 10 ohms

Magnetic field, B = 0.1 T

$\mu_o=4\pi \times 10^{-7}\ T-m/A$

Resistivity, $\rho=1.72\times 10^{-8}\ \Omega-m$

We need to find the current flowing the copper wire. Firstly, we need to find the radius of he power line using physical dimensions as :

$R=\rho \dfrac{l}{A}$

$R=\rho \dfrac{l}{\pi r^2}$

$r=\sqrt{\dfrac{\rho l}{R\pi}}$

$r=\sqrt{\dfrac{1.72\times 10^{-8}\times 7300}{10\pi}}$

r = 0.00199 m

or

$r=1.99\times 10^{-3}\ m=2\times 10^{-3}\ m$

The magnetic field on a current carrying wire is given by :

$B=\dfrac{\mu_o I}{2\pi r}$

$I=\dfrac{2\pi rB}{\mu_o}$

$I=\dfrac{2\pi \times 0.1\times 2\times 10^{-3}}{4\pi \times 10^{-7}}$

I = 1000 A

So, the current of 1000 A is flowing through the copper wire. Hence, this is the required solution.

4 0

2 years ago

If we wanted to describe and better understand the structure of the rings of Saturn, we might develop a

Svetradugi [14.3K]

The Greek philosopher Aristotle and the Roman Catholic Church also believed the sun revolved around the earth. In 1543, Nicolaus Copernicus<span> published a new theory stating the earth revolves around the sun. This is known as the Copernican theory.</span>

6 0

3 years ago

What happens when an object is dropped?

katrin2010 [14]

When an object is dropped, tossed, or kicked, as long as it is not laying on the ground, it accelerates downward, because of the force of gravity acting on it.

3 0

3 years ago

how much power is needed to lift a box with a force of 780 newtons over a distance of 2 meters in 45 seconds

-BARSIC- [3]

Answer:

Explanation:

Power is the rate at which work is done and can be found by using the formula

$p = \frac{w}{t} \\$

p is the power in Watts (W)

w is the workdone in joules

t is time in s

but workdone = force × distance

From the question

force = 780 N

distance = 2 m

workdone = 780 × 2 = 1560 N

Since we now have the value of workdone we can find the power

We have

$p = \frac{1560}{45} = 34.6666666... \\$

We have the final answer as

Hope this helps you

3 0

2 years ago