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chubhunter [2.5K]

3 years ago

5

what magnetic field is needed to exert a force of 0.4N on a 0.1m long conductor if it carries a current of 2A perpendicular to t

he magnetic field?

1 answer:

serious [3.7K]3 years ago

6 0

Answer:

2T

Explanation:

Use F = BIL

F = 0.4N

B = ??

I = 2A

L = 0.1m

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It took 1700 J of work to stretch a spring from its natural length of 2m to a length of 5m. Find the spring's force constant.

Alenkasestr [34]

The work to stretch a spring from its rest position is

   (1/2) (spring constant) (distance of the stretch)²

   E = 1/2 k x² .

You said it takes 1700 joules to stretch the spring 3 meters from its rest position, so we can write

   1700 joules = 1/2 k (3m)²

1 joule = 1 newton-meter

   1700 N-m = 1/2 k (3m)²

Multiply each side by 2: 3400 N-m = k · 9m²

Divide each side by 9m²    k = 3400 N-m / 9m²

   = (377 and 7/9)   newton per meter

7 0

3 years ago

Read 2 more answers

1. State the law of conservation of energy and what it means for you as a human considering how energy works.

Arturiano [62]

Answer: 1. The law of consevation of energy sates that energy can neither be created nor destroyed. It can only be transformed or transfered from one form to another. The law of conservation of energy is found everywhere for example, Water falls from the sky, converting potential energy to kinetic energy.

2. Different forms of energy are related because energy cannot be created or destroyed. they can all be transformed into from one form to another.

Explanation:

5 0

2 years ago

Testing shows that a sample of wood from an artifact contains 25% of the

daser333 [38]

Answer:

The artifact is 11,460 years old.

<u>Explanation</u>:

Given that,

The half life of the carbon-14 is 5730 years and we are left with 255 of the sample of wood from an arti-fact.

So it takes 5730 years for the sample to reduce into half

Initially there will be 100% of the sample so

after first 5730 years, the sample reduces into 50% percent

Now the left 50% sample will take another 5730 years to decay into half of its amount.

after next 5730 years the sample reduces into 25% percent

So totally after 2 half-life the sample reduces into 25%

That is (5730 +5730) years = 11460 years

5 0

3 years ago

Read 2 more answers

By calculating its wavelength (in nm), show that the second line in the Lyman series is UV radiation.

Rashid [163]

Answer:

λ = 102.78 nm

This radiation is in the UV range,

Explanation:

Bohr's atomic model for the hydrogen atom states that the energy is

E = - 13.606 / n²

where 13.606 eV is the ground state energy and n is an integer

an atom transition is the jump of an electron from an initial state to a final state of lesser emergy

ΔE = 13.606 (1 / $n_{f}^{2}$ - 1 / n_{i}^{2})

the so-called Lyman series occurs when the final state nf = 1, so the second line occurs when ni = 3, let's calculate the energy of the emitted photon

DE = 13.606 (1/1 - 1/3²)

DE = 12.094 eV

let's reduce the energy to the SI system

DE = 12.094 eV (1.6 10⁻¹⁹ J / 1 ev) = 10.35 10⁻¹⁹ J

let's find the wavelength is this energy, let's use Planck's equation to find the frequency

E = h f

f = E / h

f = 19.35 10⁻¹⁹ / 6.63 10⁻³⁴

f = 2.9186 10¹⁵ Hz

now we can look up the wavelength

c = λ f

λ = c / f

λ = 3 10⁸ / 2.9186 10¹⁵

λ = 1.0278 10⁻⁷ m

let's reduce to nm

λ = 102.78 nm

This radiation is in the UV range, which occurs for wavelengths less than 400 nm.

5 0

3 years ago

The total energy of a block—spring system is 0.18 J. The amplitude is 14.0 cm and the maximum speed is 1.25 m/s. Find: (a) the m

algol13

a) The mass is 0.23 kg

b) The spring constant is 1.25 N/m

c) The frequency is 1.42 Hz

d) The speed of the block is 1.08 m/s

Explanation:

a)

We can find the mass of the block by applying the law of conservation of energy: in fact, the total mechanical energy of the system (which is sum of elastic potential energy, PE, and kinetic energy, KE) is constant:

$E=PE+KE=const.$

The potential energy is given by

$PE=\frac{1}{2}kx^2$

where k is the spring constant and x is the displacement. When the block is crossing the position of equilibrium, x = 0, so all the energy is kinetic energy:

$E=KE_{max}=\frac{1}{2}mv_{max}^2$ (1)

where

m is the mass of the block

$v_{max}=1.25 m/s$ is the maximum speed

We also know that the total energy is

$E=0.18 J$

Re-arranging eq.(1), we can find the mass:

$m=\frac{2E}{v_{max}^2}=\frac{2(0.18)}{(1.25)^2}=0.23 kg$

b)

The maximum speed in a spring-mass system is also given by

$v_{max} =\sqrt{\frac{k}{m}} A$

where

k is the spring constant

m is the mass

A is the amplitude

Here we have:

$v_{max}=1.25 m/s$ is the maximum speed

m = 0.23 kg is the mass

A = 14.0 cm = 0.14 m is the amplitude

Solving for k, we find the spring constant

$k=\frac{v_{max}^2}{A^2}m=\frac{1.25^2}{0.14^2}(0.23)=18.3 N/m$

c)

The frequency in a spring-mass system is given by

$f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}$

where

k is the spring constant

m is the mass

In this problem, we have:

k = 18.3 N/m is the spring constant (found in part b)

m = 0.23 kg is the mass (found in part a)

Substituting and solving for f, we find the frequency of the system:

$f=\frac{1}{2\pi}\sqrt{\frac{18.3}{0.23}}=1.42 Hz$

d)

We can solve this part by using the law of conservation of energy; in fact, we have

$E=PE+KE=\frac{1}{2}kx^2 + \frac{1}{2}mv^2$

Where v is the speed of the system when the displacement is equal to x.

We know that the total energy of the system is

E = 0.18 J

Also we know that

k = 18.3 N/m is the spring constant

m = 0.23 kg is the mass

Substituting

x = 7.00 cm = 0.07 m

We can solve the equation to find the corresponding speed v:

$v=\sqrt{\frac{2E-kx^2}{m}}=\sqrt{\frac{2(0.18)-(18.3)(0.07)^2}{0.23}}=1.08 m/s$

#LearnwithBrainly

3 0

2 years ago