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umka21
1 month ago
13

A baseball player throws a ball straight up and catches it 3.0 s later. If the ball accelerates at 9.85 m/s2 down, at what veloc

ity did he throw the ball?
Physics
1 answer:
Softa [3K]1 month ago
7 0
Bajo una aceleración constante, se establece que al final del lanzamiento, la velocidad de la pelota es equivalente a su velocidad inicial en magnitud, pero se presenta en dirección descendente, para lo cual su signo es opuesto.
You might be interested in
A rod 150 cm long and of diameter 2.0 cm is subjected to an axial pull of 20 kn. if the modulus of elasticity of the material of
Sav [3153]
Given:
a rod with a circular cross section is experiencing uniaxial tension.
Length, L=1500 mm
radius, r = 10 mm
E=2*10^5 N/mm^2
Force, F=20 kN = 20,000 N
[note: newton (unit) in abbreviation is written in upper case, as in N ]

From the details provided, the cross-section area = π r^2 = 100 π =314 mm^2
(i) Stress,
σ
=F/A
= 20000 N / 314 mm^2
= 6366.2 N/mm^2
= 6370 N/mm^2 (to 3 significant figures)

(ii) Strain
ε
= ratio of extension / original length
= σ / E
= 6366.2 /(2*10^5)
= 0.03183 
= 0.0318 (to three significant figures)

(iii) elongation
= ε * L
= 0.03183*1500 mm
= 47.746 mm
= 47.7 mm  (to three significant figures)

5 0
1 month ago
An infinite sheet of charge, oriented perpendicular to the x-axis, passes through x = 0. It has a surface charge density σ1 = -2
Maru [3345]

1) For x = 6.6 cm, E_x=3.47\cdot 10^6 N/C

2) For x = 6.6 cm, E_y=0

3) For x = 1.45 cm, E_x=-3.76\cdot 10^6N/C

4) For x = 1.45 cm, E_y=0

5) Surface charge density at b = 4 cm: +62.75 \mu C/m^2

6) At x = 3.34 cm, the x-component of the electric field equals zero

7) Surface charge density at a = 2.9 cm: +65.25 \mu C/m^2

8) None of these regions

Explanation:

1)

The electric field from an infinite charge sheet is perpendicular to it:

E=\frac{\sigma}{2\epsilon_0}

where

\sigma is the surface charge density

\epsilon_0=8.85\cdot 10^{-12}F/m represents vacuum permittivity

Outside the slab, the electric field behaves like that of an infinite sheet.

Consequently, the electric field at x = 6.6 cm (situated to the right of both the slab and sheet) results from the combination of the fields from both:

E=E_1+E_2=\frac{\sigma_1}{2\epsilon_0}+\frac{\sigma_2}{2\epsilon_0}

where

\sigma_1=-2.5\mu C/m^2 = -2.5\cdot 10^{-6}C/m^2\\\sigma_2=64 \muC/m^2 = 64\cdot 10^{-6}C/m^2

The field from the sheet points left (negative, inward), and the slab’s field points right (positive, outward).

Thus,

E=\frac{1}{2\epsilon_0}(\sigma_1+\sigma_2)=\frac{1}{2(8.85\cdot 10^{-12})}(-2.5\cdot 10^{-6}+64\cdot 10^{-6})=3.47\cdot 10^6 N/C

and the negative sign indicates a rightward direction.

2)

Both the sheet’s and slab’s fields are perpendicular to their surfaces, directing along the x-axis, hence there's no y-component for the total field.

<pThus, the y-component totals zero.

This happens because both the sheet and slab stretch infinitely along the y-axis. Choosing any x-axis point reveals that the y-component of the field, generated by a surface element dS of either the sheet or slab, dE_y, will be equal and opposite to the corresponding component from the opposite side, -dE_y. Thus, the combined y-direction field is always zero.

3)

This scenario resembles part 1), but the point here is

x = 1.45 cm

which lies between the sheet and the slab. The fields from both contribute leftward as the slab has a negative charge (resulting in an outward field). Thus, the total field computes to

E=E_1-E_2

Replacing with expressions from part 1), we get

E=\frac{1}{2\epsilon_0}(\sigma_1-\sigma_2)=\frac{1}{2(8.85\cdot 10^{-12})}(-2.5\cdot 10^{-6}-64\cdot 10^{-6})=-3.76\cdot 10^6N/C

where the negative illustrates a leftward direction.

4)

This portion parallels part 2). Since both fields remain perpendicular to the slab and sheet, no component exists along the y-axis, thus the electric field's y-component is zero.

5)

Notably, the slab behaves as a conductor, signifying charge mobility within it.

The net charge on the slab is positive, indicating a surplus of positive charge. With the negatively charged sheet on the left of the slab, positive charges shift towards the left slab edge (at a = 2.9 cm), while negative charges move to the right edge (at b = 4 cm).

The surface charge density per unit area of the slab is

\sigma=+64\mu C/m^2

This average denotes the surface charge density on both slab sides at points a and b:

\sigma=\frac{\sigma_a+\sigma_b}{2} (1)

Additionally, the infinite sheet at x = 0 negatively charged \sigma_1=-2.5\mu C/m^2, induces an opposite net charge on the slab's left surface, thus

\sigma_a-\sigma_b = +2.5 \mu C/m^2 (2)

Having equations (1) and (2) allows for solving the surface charge densities at a and b, yielding:

\sigma_a = +65.25 \mu C/m^2\\\sigma_b = +62.75 \mu C/m^2

6)

We aim to compute the x-component of the electric field at

x = 3.34 cm

This point lies inside the slab, bounded at

a = 2.9 cm

b = 4.0 cm

In a conducting slab, the electric field remains at zero owing to charge equilibrium; thus, the x-component thereof in the slab is zero

7)

From part 5), we determined the surface charge density at x = a = 2.9 cm is \sigma_a = +65.25 \mu C/m^2

8)

As mentioned in part 6), conductors have zero electric fields internally. Since the slab is conductive, the electric field inside remains zero; therefore, the regions where the electric field is null are

2.9 cm < x < 4 cm

Thus, the suitable answer is

"none of these regions"

Learn more about electric fields:

8 0
2 months ago
On a foggy day, you are driving at 70 mph and Granny is driving at 50 mph. As you try to pass her, you both see an overturned tr
inna [3103]

Response:

C?

Reasoning:

7 0
2 months ago
If a steady-state heat transfer rate of 3 kW is conducted through a section of insulating material 1.0 m2 in cross section and 2
Maru [3345]

Answer:

\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K

Consequently, the temperature difference across the material will be \Delta T = 375 K

Explanation:

In this case, we apply the Fourier Law of heat conduction expressed by the following equation:

Q = -kA \frac{\Delta T}{\Delta x}   (1)

Where k = thermal conductivity = 0.2 W/ mK

A= 1m^2 denotes the cross-sectional area

Q= 3KW signifies the heat transfer rate

\Delta T is the temperature difference we need to determine

represents the thickness of the material\Delta x=2.5 cm =0.025 m

To isolate \Delta T from equation (1), we obtain:

\Delta T =\frac{Q \Delta x}{Ak}

Initially, we convert 3KW to W, resulting in:

Q= 3 KW* \frac{1000W}{1 Kw}= 3000 W

With all variables accounted for, we can substitute and calculate:

\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K

Thus, the temperature difference across the material will be \Delta T = 375 K

5 0
1 month ago
A 9.0-V battery moves 20 mC of charge through a circuit running from its positive terminal to its negative terminal. How much en
Yuliya22 [3333]

Answer:

The energy delivered is E = 0.18 J

Explanation:

Given,

Battery voltage, V = 9 V

Charge in the circuit, Q = 20 mC

                                        = 20 x 10³ C

Energy supplied in the circuit can be computed as

E = Q V

E = 20 x 10⁻³ x 9

E =  180 x 10⁻³

E equals 0.18 J.

The energy delivered in the circuit is therefore E = 0.18 J

7 0
1 month ago
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