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Digiron [165]
3 years ago
10

Identify the true statement. Choose one:

Physics
1 answer:
beks73 [17]3 years ago
4 0

Answer:

A. Underground coal mining is dangerous because of possible tunnel collapse and possible methane gas explosions.

Explanation:

Dangers of underground coal mining include asphyxiation, methane gas poisoning, tunnel collapse and explosions of methane gas, a highly flammable gas. Methane explosions occur since this gas is a byproduct of coal. This explosion can cause tunnel collapse.

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Very easy physics maths about current and other stuffs only one question please help me
Reil [10]

Answer:

The total voltage of the circuit is 18 volts.

Explanation:

We have, three identical resistors of resistance 3 ohms are connected in series in a circuit.

For a series combination, the equivalent resistance is given by the sum of individual resistances i.e.

R_{eq}=R_1+R_2+R_3\\\\R_{eq}=3+3+3\\\\R_{eq}=9\ \Omega

Let V is the voltage of the battery if the current in the circuit is 2 A. So,

V=IR

V=2\times 9\\\\V=18\ V

So, the total voltage of the circuit is 18 volts.

7 0
3 years ago
What is the angle between a wire carrying an 8.40 A current and the 1.20 T field it is in, if 50.0 cm of the wire experiences a
Elena L [17]

Answer:

A. 30.38°

B 5.04N

Explanation:

Using

F= ILBsin theta

2 .55N= 8.4Ax 0.5mx 1.2T x sintheta

Theta = 30.38°

B. If theta is 90°

Then

F= 8.4Ax 0.5mx 1.2x sin 90°

F= 5.04N

6 0
3 years ago
Which statement is true of a wave that’s propagating along the pavement and girders of a suspension bridge?
alexandr1967 [171]
The statement which is true of a wave that’s propagating along the pavement and girders of a suspension bridge is A. The wave is mechanical, with particles vibrating in a direction that is parallel to that of the wave, forming compressions and rarefactions.
8 0
3 years ago
Read 2 more answers
Multiple-Concept Example 9 reviews the concepts that are important in this problem. A drag racer, starting from rest, speeds up
Mademuasel [1]

Answer:

V = 90.51 m/s

Explanation:

From the given information:

Initial speed (u) = 0

Distance (S) = 391 m

Acceleration (a) = 18.9 m/s²

Using the relation for the equation of motion:

v² - u² = 2as

v² - 0² = 2as

v² = 2as

v = \sqrt{2as}

v = \sqrt{2*18.9*391}

v = 121.57 m/s

After the parachute opens:

The initial velocity = 121.57 m/ss

Distance S' = 332 m

Acceleration = -9.92 m/s²

How fast is the racer can be determined by using the relation:

V=  \sqrt{v^2 + 2aS'}

V = \sqrt{121.57^2+ 2 (-9.92)(332)}

V = 90.51 m/s

6 0
3 years ago
You hang a heavy ball with a mass of 10 kg from a gold wire 2.6 m long that is 1.6 mm in diameter. You measure the stretch of th
PolarNik [594]

<u>Answer:</u> The Young's modulus for the wire is 6.378\times 10^{10}N/m^2

<u>Explanation:</u>

Young's Modulus is defined as the ratio of stress acting on a substance to the amount of strain produced.

The equation representing Young's Modulus is:

Y=\frac{F/A}{\Delta l/l}=\frac{Fl}{A\Delta l}

where,

Y = Young's Modulus

F = force exerted by the weight  = m\times g

m = mass of the ball = 10 kg

g = acceleration due to gravity = 9.81m/s^2

l = length of wire  = 2.6 m

A = area of cross section  = \pi r^2

r = radius of the wire = \frac{d}{2}=\frac{1.6mm}{2}=0.8mm=8\times 10^{-4}m      (Conversion factor:  1 m = 1000 mm)

\Delta l = change in length  = 1.99 mm = 1.99\times 10^{-3}m

Putting values in above equation, we get:

Y=\frac{10\times 9.81\times 2.6}{(3.14\times (8\times 10^{-4})^2)\times 1.99\times 10^{-3}}\\\\Y=6.378\times 10^{10}N/m^2

Hence, the Young's modulus for the wire is 6.378\times 10^{10}N/m^2

3 0
3 years ago
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