What is the current in the 30 resistor?
A. 0.0833 A
B. 12 A
C. 2 A
D. 10 A

Answer:

W = 2 eV

Explanation:

Given that,

The wavelength of a photon = 455 nm

The kinetic energy of a photon, K = 0.73 eV

We need to find the work function of the electron. It can be solved using Einstein's equation such that,

[tex]W=E-K[/tex]

E is the energy of the photon

So,

[tex]W=\dfrac{hc}{\lambda}-K\\\\W=\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{455\times 10^{-9}\times 1.6\times 10^{-19}}-0.73\\\\W= 2.73\ eV-0.73\ eV\\\\W=2\ eV[/tex]

So, the work function of the metal is 2 eV.

Answer:

A. The hand must move with a velocity of 6.98 m/s to break the board.

B. Average force on the hand = 1025 N

Explanation:

A.To determine the speed the hand must move with to break the board, the force workdone in breaking the board is found first.

Workdone = force × distance

Minimum force required = 870 N;

Distance moved by board/Deflection in order to break = 1.4 cm = 0.014 M

Workd done = 870 N × 0.014 m = 12.18 Nm or 12.18 J

This work done = Kinetic energy of the hand

Kinetic energy = mv²/2 ; where m is mass and v is velocity

Mass of hand = 0.50 Kg, velocity = ?, K.E. = 12.18 J

v² = 2 KE/m

v = √2KE/m

v = √(2 × 12.18/0.50)

v = 6.98 m/s

Therefore, the hand must move with a velocity of 6.98 m/s to break the board.

B. Average force on the hand

This can be determined using the equation of motion, v² = u² + 2as to find acceleration, since force = mass × acceleration

From the equation of motion, a = v² - u²/2s

At rest, v = 0, u = 6.98, s = 1.2 cm = 0.012 m

a = 0² - 6.98²/ 2 × 0.012

a = -2030 m/s²

Force = 2030 m/s² × 0. 50 kg = 1015 N

Therefore, Average force on the hand = 1025 N

Answer:

effort arm mean the use of any work by using your hand force motion or by hand power

Answer:

30 m

General Formulas and Concepts:

Energy

Gravitational Potential Energy: [tex]\displaystyle U_g = mgh[/tex]

Kinetic Energy: [tex]\displaystyle KE = \frac{1}{2}mv^2[/tex]

Law of Conservation of Energy

Explanation:

Step 1: Define

Identify variables

[Given] m = 0.8 kg

[Given] g = 10 m/s²

[Given] U = 240 J

[Solve] h

Step 2: Solve for h

Answer:

[tex]F=5(240t^2i+72tj)\ N[/tex]

Explanation:

Given that,

The mass of the object, m = 5 kg

The position vector is, [tex]r=20t^4i+12t^3j[/tex]

Velocity, [tex]v=\dfrac{dr}{dt}=80t^3i+36t^2j[/tex]

Acceleration, [tex]a=\dfrac{dv}{dt}=240t^2i+72tj[/tex]

Newton's second law of motion is given as follows:

F = ma

Put all the values,

[tex]F=5(240t^2i+72tj)\ N[/tex]

Hence, this is the required solution.

Answer:

A hypothesis is a limited explanation of a phenomenon; a scientific theory is an in-depth explanation of the observed phenomenon. A law is a statement about an observed phenomenon or a unifying concept

Answer:

Explanation:

will try 2 explain fact, hypothesis, theory n law

fact is the starting pt: e.g. apple falls from tree

hypothesis tries 2 explain a fact: e.g. there is a force pulling down apple

theory is a complete explanation w/ equations n stuff: e.g. Newton came up w/ theory of gravitational attraction force

law is a theory dat has been proven right through tests n experiments: Newton's gravity theory had been proven right in many many tests.

Answer:

T = 20.84°C

Explanation:

From the law of conservation of energy:

Heat Lost by Copper Block = Heat Gained by Aluminum Calorimeter + Heat Gained by Water

[tex]m_cC_c\Delta T_c = m_wC_w\Delta T_w + m_aC_a\Delta T_a[/tex]

where,

[tex]m_c[/tex] = mass of copper = 227 g

[tex]m_w[/tex] = mass of water = 844 g

[tex]m_a[/tex] = mass of aluminum = 155 g

[tex]C_c[/tex] = specific heat capacity of calorimeter = 385 J/kg.°C

[tex]C_w[/tex] = specific heat capacity of water = 4200 J/kg.°C

[tex]C_a[/tex] = specific heat capacity of aluminum = 890 J/kg.°C

[tex]\Delta T_c[/tex] = change in temperature of copper = 283°C - T

[tex]\Delta T_w[/tex] = change in temperature of water = T - 14.6°C

[tex]\Delta T_a[/tex] = change in temperature of aluminum = T - 14.6°C

T = equilibrium temperature = ?

Therefore,

[tex](227\ g)(385\ J/kg.^oC)(283^oC-T)=(844\ g)(4200\ J/kg.^oC)(T-14.6^oC)+(155\ g)(890\ J/kg.^oC)(T-14.6^oC)\\\\24732785\ J - (87395\ J/^oC) T = (3544800\ J/^oC) T - 51754080\ J+ (137950\ J/^oC) T-2014070\ J\\\\24732785\ J +51754080\ J+2014070\ J = (3544800\ J/^oC) T+(137950\ J/^oC+(87395\ J/^oC) T\\\\78560935\ J = (3770145\ J/^oC) T\\\\T = \frac{78560935\ J}{3770145\ J/^oC}[/tex]

T = 20.84°C

Answer:

A bridge suspended by cables

Explanation:

Both objects represent a contact force (in this case, normal force) acting on each other. The force occurs since both objects are in direct physical contact.

Answer:

a)  [tex]d=11m[/tex]

b)  [tex]T=4.68s[/tex]

Explanation:

From the question we are told that:

Wavelength [tex]\lambda=22m[/tex]

Velocity [tex]v=4.6m/s[/tex]

a)

Generally the equation for distance between her and the wall d is mathematically given by

Since

The First Anti node distance is [tex]\frac{\lambda}{2}[/tex]

Therefore

 [tex]d= \frac{\22}{2}[/tex]

 [tex]d=11m[/tex]

b)

Generally the equation for her up-and-down motion is mathematically given by

 [tex]T=\frac{22}{4.7}[/tex]

 [tex]T=4.68s[/tex]

Answer:

The actual speed of the rain is 5 m/s and its direction is -53.13°

Explanation:

The actual speed of the rain V = speed of man, v + speed of rain relative to man, v'.

V = v + v'

We add these vectorially.

Since the man's speed is 3 m/s east, in the positive x - direction, we have v = 3i  and the rain's speed is falling vertically at 4 m/s, in the negative y- direction, we have v' = -4j

So, V = v + v'

V = 3i + (-4j)

V = 3i - 4j

So, the magnitude of V which is its speed is V = √(3² + (-4)²) = √(9 + 16) = √25 = 5 m/s

The direction of V, Ф = tan⁻¹(vertical component/horizontal component) = tan⁻¹(-4/3) = tan⁻¹(-4/3) = tan⁻¹(-1.333) = -53.13°

So, the actual speed of the rain is 5 m/s and its direction is -53.13°

Explanation:

No. From your own reference frame, nothing will change. Everything will look the same to you even if you're traveling at 99% speed of light. However, an outside observer will see you shrink to about 14% of your original length along the direction of your motion according to the Lorentz contraction predicted by special relativity:

[tex]L=L_{0} \sqrt{1 - \frac{v^2 }{c^2 }}[/tex]

Explanation:

The size of the force varies inversely as the square of the distance between the two charges. Therefore, if the distance between the two charges is doubled, the attraction or repulsion becomes weaker, decreasing to one-fourth of the original value.

It is Potential energy's

Answer:

British East India Company

The battle was fought at Buxar, a "small fortified town" within the territory of Bihar, located on the banks of the Ganga river about 130 kilometres (81 mi) west of Patna; it was a decisive victory for the British East India Company.

Answer:

The new voltage is 17.7 V.  

Explanation:

Voltage, V = 8.85 V

The spacing is doubled.

When it is disconnected, the charge remains same,

q = C V ..... (1)

where, C is the capacitance, V is the voltage.  

The capacitance is inversely proportional to the distance between the two plates.

So, when the spacing is doubled, the capacitance is halved.

Let the new voltage is V'.

C V = C' V'

C x 8.85 = C/2 x V'

V' = 17.7 V  

Answer:

B.

Explanation:

HNO2 is less stable thus dissociates easily to HNO3 + NO + H2O while HNO3 is a strong acid. Thus when they react with H2O they form acid rain

Answer:

B

Explanation:

dont have one just trust me

Answer:pp

Explanation:

ii

Explanation:

1. Distance, d = 5 m

Time, t = 10 s

Speed = distance/time

[tex]v=\dfrac{5}{10}=0.5\ m/s[/tex]

2. Mass, m = 10 kg

Acceleration, a = 3 m/s³

Force, F = mass (m) × acceleration (a)

F = 10 × 3

= 20 N

3. Mass, m = 7 kg

Height, h = 4 m

Potential energy, E = mgh

E = 7 × 9.8 × 4

E = 274.4 J

Hence, this is the required solution.

Answer:

Energy Bill fluctuations are inevitable and depend on a variety of different factors. Two of the most important are the current weather your home is experiencing and the current price per Kilowatt Hour (which fluctuates more than you might think).

Answer:

The acceleration of the spring at [tex]t = 3.4\,s[/tex] is -29339.947 centimeters per square second.

Explanation:

The mass-spring system experiments a Simple Harmonic Motion, whose kinematic expression is the following:

[tex]x(t) = A\cdot \cos \left(\sqrt{\frac{k}{m} }\cdot t + \phi\right)[/tex] (1)

Where:

[tex]x(t)[/tex] - Position, in centimeters.

[tex]A[/tex] - Amplitude, in centimeters.

[tex]k[/tex] - Spring constant, in newtons per meter.

[tex]m[/tex] - Mass, in kilograms.

[tex]\phi[/tex] - Phase, in radians.

By Differential Calculus, we derive expression for the velocity and acceleration of the mass-spring system:

[tex]v(t) = -\sqrt{\frac{k}{m} }\cdot A\cdot \sin \left(\sqrt{\frac{k}{m} }\cdot t +\phi\right)[/tex] (2)

[tex]a(t) = -\frac{k\cdot A}{m}\cdot \cos \left(\sqrt{\frac{k}{m} }\cdot t +\phi\right)[/tex] (3)

Where [tex]v(t)[/tex] and [tex]a(t)[/tex] are the velocity and acceleration of the system, in centimeters per second and centimeters per square second, respectively.

If we know [tex]m = 2.7\,kg[/tex], [tex]k = 159\,\frac{N}{m}[/tex], [tex]t = 0\,s[/tex], [tex]x(t) = 19\,cm[/tex] and [tex]v(t) = -13\,\frac{cm}{s}[/tex], then we have the following system of nonlinear equations:

[tex]A \cdot \cos \phi = 19[/tex] (1)

[tex]-7.674\cdot A \cdot \sin \phi = - 13[/tex] (2)

If we divide (2) by (1):

[tex]-7.674\cdot \tan \phi = -0.684[/tex]

[tex]\tan \phi = 0.089[/tex]

[tex]\phi = \tan^{-1} 0.089[/tex]

[tex]\phi \approx 0.028\,rad[/tex]

By (1), we get the value of the amplitude:

[tex]A = \frac{19}{\cos \phi}[/tex]

[tex]A = 19.075\,cm[/tex]

If we know that [tex]A = 19.075\,cm[/tex], [tex]k = 159\,\frac{N}{m}[/tex], [tex]m = 2.7\,kg[/tex], [tex]t = 3.4\,s[/tex] and [tex]\phi \approx 0.028\,rad[/tex], then the acceleration of the spring is:

[tex]a(t) = -29339.947\,\frac{cm}{s^{2}}[/tex]

The acceleration of the spring at [tex]t = 3.4\,s[/tex] is -29339.947 centimeters per square second.

Built by 1800, it was the home of inventor Jethro Wood (1774-1834), whose 1819 invention of an iron moldboard plow revolutionized American agriculture.

Answer:

122.5 ohm

Explanation:

Given :

P=40 w

V= 70 V

R=?

Resistance can be calculated as :

[tex]P=\frac{V^{2} }{R} \\40=\frac{(70)^{2} }{R}\\40=\frac{4900}{R} \\R=\frac{4900}{40} \\R=122.5 ohm[/tex]

Therefore, resistance of the bulb will be 122.5 ohm

Answer:

120 beats per minute.

Explanation:

If I take your pulse and observe 80 heartbeats in a minute. Then the period of your heartbeat is 0.8 s and frequency is 1.3Hz.

A pulse is the term used in medicine to describe the tactile arterial palpation of the cardiac cycle (heartbeat) by skilled fingertips. Any location where an artery can be compressed close to the surface of the body, such as the carotid artery in the neck, the radial artery in the wrist, the femoral artery in the groyne, the popliteal artery behind the knee, the posterior tibial artery near the ankle joint, and on the foot, can be used to palpate the pulse (dorsalis pedis artery). Heart rate may be determined by monitoring pulse, or the number of arterial pulses per minute. Auscultation, which is the process of counting the heartbeats while listening to the heart using a stethoscope, is another way to determine the heart rate. Typically, three fingers are used to gauge the radial pulse.

Given,

heart beat = 80 beats/min = 1.3 beats/s

Frequency is nothing but how much beats is heart having in one second and that is 1.3 beats/s. Hence frequency of heart is 1.3Hz.

The Period is reciprocal of frequency,

T = 1/f = 0.8 s

To know more about frequency :

https://brainly.com/question/29739263

#SPJ2.

Answer:

C. S + 02 → S02

Explanation:

A synthesis or combination reaction is that reaction involving two elements as reactants to form a single compound as product.

In the reaction given below;

S + 02 → S02

Sulphur and oxygen are elemental substances that combine to synthesize sulfur IV oxide (SO2), and hence it is an example of synthesis reaction.

Answer:

9213 J

Explanation:

Change in Kinetic energy = Change in Potential energy

= 12,928J - 3715J

=9213 J

For more assistance: +1 (304) 223-3136

Answer:

Boyle's law.

Explanation:

Robert Boyle was an Irish chemist and is famously referred to as the first modern chemist. He was born on the 25th of January, 1627 in Lismore, Ireland and died on the 31st, December 1691, London, United Kingdom.

Boyles states that when the temperature of an ideal gas is kept constant, the pressure of the gas is inversely proportional to the volume occupied by the gas.

Mathematically, Boyles law is given by;

[tex] PV = K[/tex]

[tex] P_{1}V_{1} = P_{2}V_{2} [/tex]

Where;

P1 is the original pressure.

P2 is the final pressure.

V1 is the original volume.

V2 is the final volume.

Hence, when you release some of the paint from a spray paint can by applying an amount of pressure and the can remains at the same temperature, the gas law which this represent is Boyle's law.

Answer: 4800 N/m

Explanation:

Given

mass of rock [tex]m=2.5\ kg[/tex]

Height of cliff [tex]h=32\ m[/tex]

compression in the spring [tex]x=57\ cm[/tex]

Here, potential energy is converted into kinetic energy which in turn converts to elastic potential energy of the spring

[tex]\Rightarrow mgh=\dfrac{1}{2}kx^2\\\\\Rightarrow k=\dfrac{2mgh}{x^2}\\\\\Rightarrow k=\dfrac{1568}{0.3249}\\\\\Rightarrow k=4826.100\approx 4800\ N/m[/tex]

Answer:

480

Explanation:

2021

Explanation:

1. First, let's find the total resistance of the circuit. We begin by combining [tex]R_{4}[/tex], [tex]R_{5}[/tex] and [tex]R_{6}[/tex]:

[tex]R_{456}=R_{4} + \dfrac{R_{5}R_{6}}{R_{5} + R_{6}}[/tex]

[tex]= 6\:Ω + \dfrac{(3\:Ω)(5\:Ω)}{3\:Ω+5\:Ω} = 7.9\:Ω[/tex]

Now time to combine [tex]R_{2}[/tex] and [tex]R_{3}[/tex] and they are connected in series so

[tex]R_{23} =R_{2} + R_{3} = 17\:Ω[/tex]

Note that [tex]R_{23}[/tex] and [tex]R_{456}[/tex] are connected in parallel so

[tex]R_{23456} = \dfrac{R_{23}R_{456}}{R_{23}+R_{456}}=5.4\:Ω[/tex]

Finally, [tex]R_{23456}[/tex] is connected in series with [tex]R_{1}[/tex] so the total resistance [tex]R_{T}[/tex] is

[tex]R_{T} = R_{1} + R_{23456} = 10\:Ω + 5.4\:Ω = 15.4\:Ω[/tex]

2. The total current in the circuit is

[tex]I_{T} = \dfrac{V}{R_{T}} = \dfrac{20\:V}{15.4\:Ω} = 1.3\:A[/tex]

3. The voltage drop across [tex]R_{1},\:V_{1}[/tex] is

[tex]V_{1} = I_{T}R_{1} = (1.3\:A)(10\:Ω) = 13\:V[/tex]

4. We can see that [tex]I_{T} = I_{1} + I_{2}[/tex]. To solve for [tex]I_{1}[/tex], we need [tex]V_{23}[/tex], which is just [tex]V_{T} - V_{1} = 20\:V - 13\:V = 7\:V[/tex] , which gives us

[tex]I_{1} = \dfrac{V_{23}}{R_{23}} = \dfrac{7\:V}{17\:Ω} = 0.4\:A[/tex]

5. From #2 & #4, [tex]I_{2} = 1.3\:A - 0.4\:A = 0.9\:A[/tex] and we also know that the voltage drop across [tex]R_{456}[/tex] is 7 V, the same as that of [tex]R_{23}[/tex]. The voltage drop across [tex]R_{4}[/tex] is

[tex]V_{4} = I_{2}R_{4} =(0.9\:A)(6\:Ω) = 5.4\:V[/tex]

This means that the voltage drop across [tex]R_{6}[/tex] is 7 V - 5.4 V = 1.6 V. Knowing this, the current through [tex]R_{6}[/tex] is

[tex]I_{6} = \dfrac{1.6\:V}{5\:Ω} = 0.3\:A[/tex]