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3 years ago

12

By what length will a slab of concrete that is originally 18 m long contract when the temperature drops from 24°C to -16°C? The

coefficient of linear thermal expansion for this concrete is 1.0 × 10-5 C-1.

1 answer:

RUDIKE [14]3 years ago

4 0

Explanation:

According to Thermal Expansion of solids:

$dl = \alpha \times l \times dt$

$dl = {10}^{ - 5} \times 18 \times 40$

$dl = 7.2 \times {10}^{ - 3}$

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marishachu [46]

Answer:

The box will experience an acceleration.

Explanation:

Here, 2 N and 3 N forces are acting opposite to each other. In this case, the net force experience by the box would be (3-2)N = 1 N towards right. Since acceleration is directly proportional to the net force, therefore the box will experience an acceleration.

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3 years ago

Denial cycled at 6 mph for 0.8 h. Then he jogged at 2 mph for

dexar [7]

<h3>Deniel's average speed for the total</h3><h3>distance is 3.6 mph</h3>

Average speed is difined as the total distance travelled divided by the total time required to cover the distance. Mathematically, it is expressed as:

$Ave. Speed = \frac{Total distance }{Total time}$

To obtain the average speed of Daniel, we shall determine the distance travelled in each case. This is illustrated below:

<h3>Case 1:</h3>

Speed 1 (S₁) = 6 mph

Time 1 (t₁) = 0.8 h.

<h3>Distance 1 (D₁) =? </h3>

$Speed = \frac{Distance}{Time} \\\\S_{1} = \frac{D_{1}}{t_{1}} \\\\6 = \frac{D_{1}}{0.8}$

Cross multiply

D₁ = 6 × 0.8

<h3>D₁ = 4.8 mile</h3>

<h3>Case 2:</h3>

Speed 2 (S₂) = 2 mph

Time 2 (t₂) = 1.2 h.

<h3>Distance 2 (D₂) =? </h3>

$S_{2} = \frac{D_{2}}{t_{2}}\\\\2 = \frac{D_{2}}{1.2}$

Cross multiply

D₂ = 2 × 1.2

<h3>D₂ = 2.4 mile </h3>

Next, we shall determine the total time. This can be obtained as follow:

Time 1 (t₁) = 0.8 h.

Time 2 (t₂) = 1.2 h.

<h3>Total time (T) =? </h3>

T = t₁ + t₂

T = 0.8 + 1.2

<h3>T = 2 h</h3>

Next, we shall determine the total distance. This can be obtained as follow:

Distance 1 (D₁) = 4.8 mile

Distance 2 (D₂) = 2.4 mile

<h3>Total distance (D) =?</h3>

D = D₁ + D₂

D = 4.8 + 2.4

<h3>D = 7.2 mile</h3>

Finally, we shall determine the average speed of Daniel. This can be obtained as follow:

Total time = 2 h

Total distance = 7.2 mile

<h3>Average speed =?</h3>

$Ave. speed = \frac{Total distance }{Total time} \\\\Ave. speed = \frac{7.2 }{2}$

<h3>Average speed = 3.6 mph</h3><h3 />

Therefore, the average speed of Daniel is 3.6 mph

Learn more: brainly.com/question/680492

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3 years ago

Psychology is a<br><br>A) science <br><br>B) philosophy <br><br>C) theory <br><br>D) opinion

yan [13]

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3 years ago

What has been gravity's apparent role in our solar system so far? Focus on the formation of planets, individual orbits, alignmen

masya89 [10]

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3 years ago

cestrela7 [59]

Hello,

<span>A police car parked on the side of the highway emits a 1200 Hz sound that bounces off a vehicle farther down the highway and returns with a frequency of 1250 Hz.

How fast is the vehicle going?

Doppler equation formula: </span>ƒL = ƒS(v - vL)/(v - vS)

The wave returns with a frequency of 1250 Hz, the <span>echo frequency is higher; the car must be traveling towards the police car.

</span><span>The wave echo is coming back towards the police car at the same speed as the sound wave travels towards the moving car so t</span><span>he relative speed between the cars is half of the speed of the echo.

* </span><span>speed of sound equals about 337 m/s </span>

2v / 337 = (1250/1200) - 1
<span>2v = 14.04 m/s </span>
<span>v = 7.02 m/s
</span>
Thus, the vehicle is going 7.02 m/s.

Faith xoxo

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4 years ago