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2 years ago

Which is true of magnetic field lines, but not electric field lines

Physics

2 answers:

Fed [463]2 years ago

8 0

Answer:

B) they show which way iron shavings would align themselves

Explanation:

Stels [109]2 years ago

7 0

Answer:

B) they show which way iron shavings would align themselves

Explanation:

Let's analyze each statement:

A) they are not affected by their own source --> this is true for both magnetic and electric fields. In fact, both fields are produced (and so affected) by a source (a magnet or a current in the magnetic field case, and an electric charge in the electric field case)

B) they show which way iron shavings would align themselves --> this is only true for the magnetic field. In fact, the pieces of iron will align according to the magnetic field; however, since they are electrically neutral, they are not affected at all by an electric field.

C) they re stronger near the source and get weaker farther away --> true for both magnetic and electric fields.

D) the closer the fields lines, the stronger the fields --> also true for both magnetic and electric fields.

So, the correct answer is B.

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A baseball player slides into third base with an initial speed of 4.0 m/s. If the coefficient of

musickatia [10]

The frictional force is given by F = μmg

where μ is the coeficient of friction. 

Work done by frictional force = Fd = μmgd 

Kinetic energy "lost" = 1/2 mv² 

Fd = μmgd = 1/2 mv² 

The m's cancel μgd = v² / 2 

d = v² / 2μg 

d = 8² / 2(0.41)(9.8) 

d = 32 / (0.41)(9.8) 

d = 7.96 

Player slides 8 m . 

Note. In your other example μ = 0.46 and v = 4 m/s 

d = v² / 2μg 

= 4² / 2(0.46)(9.8) 

= 8 / (0.46)(9.8) 

= 1.77 or 1.8 m.

Hope i Helped :D

3 0

3 years ago

Read 2 more answers

A thin spherical spherical shell of radius R which carried a uniform surface charge density σ. Write an expression for the volum

ozzi

Answer:

Explanation:

From the given information:

We know that the thin spherical shell is on a uniform surface which implies that both the inside and outside the charge of the sphere are equal, Then

The volume charge distribution relates to the radial direction at r = R

∴

$\rho (r) \ \alpha \ \delta (r -R)$

$\rho (r) = k \ \delta (r -R) \ \ at \ \ (r = R)$

$\rho (r) = 0\ \ since \ r< R \ \ or \ \ r>R---- (1)$

To find the constant k, we examine the total charge Q which is:

$Q = \int \rho (r) \ dV = \int \sigma \times dA$

$Q = \int \rho (r) \ dV = \sigma \times4 \pi R^2$

∴

$\int ^{2 \pi}_{0} \int ^{\pi}_{0} \int ^{R}_{0} \rho (r) r^2sin \theta \ dr \ d\theta \ d\phi = \sigma \times 4 \pi R^2$

$\int^{2 \pi}_{0} d \phi* \int ^{\pi}_{0} \ sin \theta d \theta * \int ^{R}_{0} k \delta (r -R) * r^2dr = \sigma \times 4 \pi R^2$

$(2 \pi)(2) * \int ^{R}_{0} k \delta (r -R) * r^2dr = \sigma \times 4 \pi R^2$

Thus;

$k * 4 \pi \int ^{R}_{0} \delta (r -R) * r^2dr = \sigma \times R^2$

$k * \int ^{R}_{0} \delta (r -R) r^2dr = \sigma \times R^2$

$k * R^2= \sigma \times R^2$

$k = R^2 --- (2)$

Hence, from equation (1), if k = $\sigma$

$\mathbf{\rho (r) = \delta* \delta (r -R) \ \ at \ \ (r=R)}$

$\mathbf{\rho (r) =0 \ \ at \ \ rR}$

To verify the units:

$\mathbf{\rho (r) =\sigma \ * \ \delta (r-R)}$

↓ ↓ ↓

c/m³ c/m³ × 1/m

Thus, the units are verified.

The integrated charge Q

$Q = \int \rho (r) \ dV \\ \\ Q = \int ^{2 \ \pi}_{0} \int ^{\pi}_{0} \int ^R_0 \rho (r) \ \ r^2 \ \ sin \theta \ dr \ d\theta \ d \phi \\ \\ Q = \int ^{2 \pi}_{0} \ d \phi \int ^{\pi}_{0} \ sin \theta \int ^R_{0} \rho (r) r^2 \ dr$

$Q = (2 \pi) (2) \int ^R_0 \sigma * \delta (r-R) r^2 \ dr$

$Q = 4 \pi \sigma \int ^R_0 * \delta (r-R) r^2 \ dr$

$Q = 4 \pi \sigma *R^2$ since $( \int ^{xo}_{0} (x -x_o) f(x) \ dx = f(x_o) )$

$\mathbf{Q = 4 \pi R^2 \sigma }$

6 0

3 years ago

speed of sound is 343 Ms at 20 degrees Celsius. The frequency heard from the sound is 256 Hz. what is the sounds wavelength?

Lina20 [59]

S= 343m/s
F=256Hz

WL= 343ms/256-1
WL=V/F

= 1.339844m

7 0

3 years ago

When the activation energy of an exothermic reaction decreases at a given temperature, the reaction rate increases because the _

fgiga [73]

When the activation energy of an exothermic reaction decreases at a given temperature, the reaction rate increases because the number of successful effective collisions is higher. More of the reactants collide and are able to form products. Hope this answers the question. have a nice day.

6 0

3 years ago

The constant forces F1 = 8 + 29 + 32 N and F2 = 48 - 59 - 22 N act together on a particle during a displacement from the point A

steposvetlana [31]

Answer:

- 600 J

Explanation:

A (20, 15, 0 ) m

B (0, 0, 7) m

$\overrightarrow{F_{1}}=8\widehat{i}+29\widehat{j}+32\widehat{k}$