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2 years ago

What is the new current?

Physics

1 answer:

nikdorinn [45]2 years ago

3 0

Voltage = current x resistance
since R is doubled, current must reduce by half.
So,
new current = 120/2 = 60mA

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Which of the following situations would cause the greatest decrease in the motion of molecules in a system?

Alina [70]

A. is the right answer since work is negative and Q which is heat in negative also

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2 years ago

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PS Final Exam

tatuchka [14]

Answer:

rolling friction

Explanation:

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2 years ago

an eagle has a mass of 8 kg and is flying 85 m above he ground with a speed of 20 m/s. what is the total mechanical energy of th

antoniya [11.8K]

85+5=90 :DD
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3 years ago

An aluminum wire is held between two clamps under zero tension at room temperature. Reducing the temperature, which results in a

Blababa [14]

Answer:

$\frac{\Delta L}{L} =5.37\times 10^{-4}$

Explanation:

Given:

cross sectional area of the wire, $A=5.75\times 10^{-6}\ m^2$

density of aluminium wire, $\rho=2.7\times 10^3\ kg.m^{-3}$

young's modulus of the material, $E=7\times 10^{10}\ N.m^{-2}$

wave speed, $v=118\ m.s^{-1}$

<u>We have mathematical expression for strain as:</u>

$\frac{\Delta L}{L} =\frac{\sigma}{E}$ ...............................(1)

and since, $\sigma =\frac{T}{A}$

where, T = tension force in the wire

equation (1) becomes:

$\frac{\Delta L}{L} =\frac{T}{A.E}$ ............................(2)

<u>Also velocity ofwave in tensed wire:</u>

$v=\sqrt{\frac{T}{\mu} }$ ...................................(3)

where: $\mu=$ linear mass density of the wire

$\therefore \mu=\rho \times A$

Now, equation (3) becomes

$v=\sqrt{\frac{T}{\rho \times A} }$

$T=v^2.\rho \times A$ ............................(4)

Using eq. (2) & (4) for tension T

$v^2.\rho \times A=A.E\times \frac{\Delta L}{L}$

$\frac{\Delta L}{L} =\frac{v^2.\rho}{E}$

putting the respective values

$\frac{\Delta L}{L} =\frac{118^2\times 2.7\times 10^3}{7\times 10^{10}}$

$\frac{\Delta L}{L} =5.37\times 10^{-4}$

6 0

2 years ago

Nicholas sends 20.0 minutes ironing shirts with his 1800-watt irn . How many joules of energy were usedby the iron

Nuetrik [128]

1 watt = 1 joule/sec
1800 watts = 1800 joules/sec

   (1800 J/sec) x (20 min) x (60 sec/min)

   = (1800 x 20 x 60) joules = 2,160,000 joules .

   ( 2.16 megajoules )

6 0

3 years ago