Answer:
The initial speed of the block is 1.09 m/s
Explanation:
Given;
mass of block, m = 1.7 kg
force constant of the spring, k = 955 N/m
compression of the spring, x = 4.6 cm = 0.046 m
From principle of conservation of energy
kinetic energy of the block = elastic potential energy of the spring
¹/₂mv² = ¹/₂kx²
mv² = kx²
[tex]v = \sqrt{\frac{kx^2}{m} }[/tex]
where;
v is the initial speed of the block
x is the compression of the spring
[tex]v = \sqrt{\frac{955*(0.046)^2}{1.7} } \\\\v = 1.09 \ m/s[/tex]
Therefore, the initial speed of the block is 1.09 m/s
Given a permanent magnet with known magnetic poles and a beam of electrons, how can you show that the electrons are negatively charged
Answer:
To prove that the electron is negatively charged, first we orient the direction of the magnetic field of the permanent magnet to enter into this computer screen.
Next we focus the beam of electrons to cut across the magnetic field perpendicularly, flowing from the right side of this screen to the left side.
If the electron beam is deflected upwards, then the electrons in the electron beam are negatively charged.
To check, we know that Lorentz left hand rule for a negatively charged particle moving through a magnetic field states that "if the left hand is held out with the fingers parallel to one another, and the thumb at a 90° angle to the rest of the fingers, then the fingers represents and points in the direction of the magnetic field, and the thumb represents and points in the direction of the negative charge through the magnetic field. The palm of the left hand will push in the direction of the force on the negatively charged particle."
Find "x" at: x = Cos4377π + 8Sen750 ° Select one:
a. 1/3
b. 2
C. 1/2
d. 3
Answer:
d. 3
Explanation:
x = cos(4377π) + 8 sin(750°)
A full circle is 2π radians or 360°.
x = cos(4377π − 4376π) + 8 sin(750° − 720°)
x = cos(π) + 8 sin(30°)
x = -1 + 8 (1/2)
x = 3
A remote-controlled toy car travels at a constant speed of 3 m/s. What distance does the car travel in 6 seconds?
Answer:
speed=d/t.
3=d/6.
d=3×6=18m
You are looking down on a N = 17 turn coil in a magnetic field B = 0.5 T which points directly down into the screen. If the diameter of the coil d = 3.8 cm, and the field goes to zero in t = 0.24 seconds, what would be the magnitude of the voltage (in Volts) and direction of the induced current? Indicate the direction of the current by the sign in front of your voltage: counterclockwise is positive, clockwise is negative.
Complete Question
The diagram for this question is shown on the first uploaded image
Answer:
The voltage is [tex]\epsilon = 0.40163 \ V[/tex]
The direction of the induced current is clockwise
Explanation:
From the question we are told that
The number of turns is N = 17
The magnetic field is [tex]B_2 = 0.5 \ T[/tex]
The diameter is [tex]d = 3.8 \ cm = 0.038 \ m[/tex]
The time interval is [tex]dt = 0.24 \ s[/tex]
The induce emf is mathematically represented as
[tex]\epsilon = - N \frac{d\phi}{dt}[/tex]
[tex]\epsilon = - N \frac{d ( B_2 - B_1 ) A }{dt}[/tex]
Here [tex]B_1[/tex] is the magnetic field experienced by the coil before entering the magnetic field given in the question i.e [tex]B_1 = 0[/tex]
Here the negative sign show that the induced voltage is moving in a direction opposite to the change magnetic flux
The area is mathematically represented as
[tex]A = \pi \frac{d^2}{4}[/tex]
=> [tex]A = 3.142 * \frac{ 0.038^2 }{4}[/tex]
=> [tex]A = 0.01134 \ m^2[/tex]
Hence
[tex]\epsilon = - 17 * \frac{ 0.5 * 0.01134 }{ 0.24}[/tex]
[tex]\epsilon = 0.40163 \ V[/tex]
The direction of the induced current is the same as that of induced voltage
Thus the direction is clockwise
Can someone please solve these 6 questions and explain briefly? I really do not understand them. Thank you
Explanation:
Use SOH-CAH-TOA.
Sine = Opposite / Hypotenuse
Cosine = Adjacent / Hypotenuse
Tangent = Opposite / Adjacent
For example, in 2(a), we are given an angle and the hypotenuse. We want to find the side adjacent to the angle. Therefore, we should use cosine.
cos 58° = y / 32.3
y = 32.3 cos 58°
y ≈ 17.1
In 3(a), we are given the adjacent side and opposite side. We want to find the angle. So use tangent.
tan θ = 3.6 / 6.2
θ = tan⁻¹(3.6/6.2)
θ = 30.1°
In 4(a), we are given an angle and the hypotenuse. We want to find the side opposite of the angle. Therefore, we should use sine.
sin 47° = x / 29
x = 29 sin 47°
x ≈ 21.2
HELP ASAP PLZ
What is the most likely reason for using the following model? A diagram that shows the different layers inside the sun Image © 2010 NASA The object is too small. The object represents a set of data. The object cannot be directly observed. The object represents a prediction about the future.
Answer:
Option C, The object cannot be directly observed.
Explanation:The temperature of sun is extremely high due to which it is almost impossible to land on its surface and explore the depth of it. Thus a prototype of it is required to predict its probable internal structure and associated feature which effect our planet "earth".
This prototype/model is based on the deduction arrived after analyzing the satellite information available in the form of high resolution images.
Hence, option C is correct
Answer:
The answer is c the object cannot be directly observed.
Explanation:
I took the test and got it right.
A block sliding along a horizontal frictionless surface with speed v collides with a spring and compresses it by 1.0 cm . What will be the compression if the same block collides with the spring at a speed of 4v
Answer:
The compression is [tex]x = 0.05 \ m[/tex]
Explanation:
From the question we are told that
The first velocity is v
The compression of the spring is [tex]d = 1.0 \ cm = 0.01 \ m[/tex]
The second velocity is 4v
Generally according to the law of energy conservation
The kinetic energy of the block is equal to the energy stored in the spring that is
[tex]\frac{1}{2} * m* v^ 2 = \frac{1}{2} * k * d^2[/tex]
For first speed
[tex]m* v^ 2 = k * 0.01^2[/tex]
=> [tex]m* v^ 2 = k * 0.0001[/tex]
=> [tex]k = \frac{ m v^2 }{ 0.0001}[/tex]
For second speed
[tex]\frac{1}{2} * m* (5v)^ 2 = \frac{1}{2} * k * x^2[/tex]
=> [tex]12.5mv^2 = 0.5 k x^2[/tex]
substituting for k
=> [tex]12.5mv^2 = 0.5 (\frac{mv^2}{0.0001} ) x^2[/tex]
=> [tex]12.5 = 5000x^2[/tex]
=> [tex]x = 0.05 \ m[/tex]
A charged particle has mass 1.20kg and charge negative 0.002C. It is moving. There is a uniform magnetic field of strength 0.25T pointing in the positive z direction present everywhere in the room. The particle experiences a magnetic force of 0.015N in the positive x direction. What is the velocity of the particle
Answer:
The velocity of the particle is 30 m/s.
Explanation:
The velocity can be found using Lorentz force:
[tex] F = q*v \times B [/tex]
Where:
q: is the charge of the particle = 0.002 C
v: is the velocity of the particle
B: is the magnetic field = 0.25 T
F: is the magnetic force = 0.015 N
Since the magnetic field and the particle's velocity are orthogonal, the cross product is equal to the product of the absolutes values of v and B.
We have:
[tex] F = q|v||B| [/tex]
[tex] v = \frac{F}{qB} = \frac{0.015 N}{0.002 C*0.25 T} = 30 m/s [/tex]
Therefore, the velocity of the particle is 30 m/s.
I hope it helps you!
A boy weighing 70 kg is standing on the sand. Calculate the pressure on if you are resting on your feet, whose surfaces add up to 0.035 m2 and if you are resting on diving fins of 0.300 × 0.42 m each
Explanation:
Pressure = force / area
If you are standing on your feet:
P = (70 kg × 10 m/s²) / (0.035 m²)
P = 20,000 Pa
If you are standing on diving fins:
P = (70 kg × 10 m/s²) / (2 × 0.30 m × 0.42 m)
P ≈ 2,800 Pa
When reading a digital volt-ohmmeter (DVOM), you have a reading of 2168 mV, which is the same as:__________
A. 2168 millivolts.
B. 2.168 volts.
C. 1000 mV.
D. Both A and B
Answer:
D, both A and B
Explanation:
2168 mV is the SI unit for potential difference and the Voltmeter.
The primary unit is Volt, represented as V. Due to the fact that there can be a much higher reading, or an even much more smaller one, comes the need for variants of the same unit.
10^-3 is called milli and represented as m
10^3 is called killo and represented as k
10^-6 is called micro and represented as µ
10^6 is called mega and represented as M
and even much higher variants of up to 10^12 and 10^-12
As we can see from the aforementioned example, 10^-3 is milli and represented as m
And our question gave us the unit in mV, which stands for millivolts.
Also, if we look at option B, it states, 2.168 volts. This 2.168 volts is also the same thing as A. Take a look at it this way, I said mV is 10^-3, right?
So, 2168*10^-3 is also 2168/100 which is 2.168. The only difference here is, once we make this conversion from mV, we have to drop the milli tag, because we have already made a conversion, and thus, leave it as V.
2168 mV = 2.168V
Hence why we picked option D, Both A & B as the right one
An object is released from rest and falls a distance h during the first second of time. How far will it fall during the next second of time? Explain.
a. 2h
b. 4h
c. h
d. h^2
e. 3h
Answer:
E. 3h
Explanation:
We know that
u = 0 m/s.
velocity after t = 1s
v = u+gt = 0+9.81 x 1s= 9.81 m/s
distance covered in 1st sec
= =>> ut+0.5 x g x t²
=>>0 + 0.5x 9.81 x 1 = 4.90m
Let 4.90 be h
distance travelled in 2nd second will now be used
So velocity after t = 1s
=>>1 x t+ 0.5 x g x t²
=>9.81x 1 + 0.5 x 9.81 x 1 = 3 x 4.90
So since h= 4.90
Then the ans is 3x h = 3h
A superball has a coefficient of restitution of .90. The ball is dropped from an intitial height of 1.60m.
a) if the ball is allowed to bounce 3 times, how high will it rebound after the third bounce?
b) If the ball has a mass of 48g, calculate the amount of the ball's orignal energy that was lost in the three impacts with the floor.
Answer:
a
[tex]H_3 = 0.85 \ m[/tex]
b
[tex]PE = 0.3528 \ J[/tex]
Explanation:
From the question we are told that
The coefficient of resolution is [tex]C_r = 0.90[/tex]
The initial height is [tex]H_i = 1.60 \ m[/tex]
Considering question a
The number of times the ball bounced is [tex]k = 3[/tex]
Generally the height attained after the 3rd bounce is mathematically represented as
[tex]H_3 = H_i * (C_r)^{2 * k }[/tex]
=> [tex]H_3 = 1.60 * 0.90^{2 * 3 }[/tex]
=> [tex]H_3 = 0.85 \ m[/tex]
Considering question b
The mass is m = 48 g = 0.048 kg
Generally the amount of potential energy that was lost is mathematically represented as
[tex]PE = mg [ H_i - H_3 ][/tex]
=> [tex]PE = 0.048 * 9.8 [1.60 - 0.85 ][/tex]
=> [tex]PE = 0.3528 \ J[/tex]
If an ancient campfire were analyzed, was found to have only about one-eighth the carbon-14 that is normally found in living things, how long ago was that campfire extinguished? Answer in units of y.
Answer:
17047.54 years or 17048 y
Explanation:
From;
0.693/t1/2 = 2.303/t log (Ao/A)
Where;
t1/2=half-life of the carbon-14 =5670 years
t= time elapsed
Ao= activity of living C-14
A= activity if the sample under study
But A= 1/8 Ao
Hence;
0.693/5670= 2.303/t log(Ao/1/8Ao)
1.22×10^-4 = 2.303/t log 8
1.22×10^-4 = 2.0798/t
t= 2.0798/1.22×10^-4
t= 17047.54 years
The magnetic flux through a coil of wire containing two loops changes at a constant rate from -83 Wb to 82 Wb in 0.39 s .
What is the magnitude of the emf induced in the coil?
Answer:
423v
Explanation:
Using
E= -N ∆န/ ∆ t
= ( -1) X (-83 - 82)/0.39
= 423volts
The first step when doing
an
investigation is the observe a situation. True or false?
Answer:
True! First step is to make objective observations.
Which type of graph uses wedges to show the amount of data points in a
category?
A. Circle graph
O B. Line graph
O C. Box-and-whisker plot
D. Stemplot
The type of graph that uses wedges to show the amount of data points in a category is a Circle graph, also known as a Pie chart. In a Pie chart, the circle represents the whole data set, and each wedge represents a specific category or data point.
In a Circle graph, the entire circle represents the total amount or the whole data set being analyzed. The circle is divided into wedges or slices, with each wedge representing a specific category or data point. The size of each wedge is proportional to the amount or percentage of data points that belong to that category.
The wedges are typically labeled with the category they represent and are often accompanied by a numerical value or percentage to indicate the exact proportion of data points in that category. The labels and values help the reader interpret the graph and understand the distribution of data across different categories.
Therefore, the correct answer is A. Circle graph.
For more information regarding the Pie chart, visit:
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If a ball is accelerating down through the air with no horizontal motion, what must be true about the net forces acting on the ball?(1 point) The net force on the ball is directed upward. The net force on the ball is zero. The gravitational force is greater than the drag. The drag is greater than the gravitational force.
Answer:
The net force on the ball is zero.
Explanation:
Newton's first law of motion states that an object will remain in the same state of motion or at rest unless a resultant force acts on it, and if the net force on an object is zero, then that means that the object will keep moving at the same acceleration or the object stays stationary.
So, the truth about the net forces acting on the ball is that the net force on the ball is zero.
Answer:
The gravitational force is greater than the drag.
Explanation:
I took the quick check and got it wrong when I chose The net force on the ball is zero but I was right the first time with the third answer choice listed in the question.
A vertical tube one meter long is open at the top. It is filled with 75 cm of water. If the velocity of sound is 344 m/s, what will the fundamental resonant frequency be (in Hz)?
Answer:
344Hz
Explanation:
First we need to more that the frequency will inky resonate in the portion not containing water. If the total length is 1m and the filled with water up to 75cm, the length of the air column will be 100cm - 75cm = 25cm
Fundamental frequency of a closed pipe fo = V/4L
V is the velocity of sound in air
L is the length of the air column
Given V = 344m/s
L = 25cm = 0.25m
fundamental resonant frequency = 344/4(0.25)
= 344/1
= 344Hz
Which planet is terrestrial? Jupiter Mars Saturn Uranus
Answer: The planet Mars is terrestrial.
Terrestrial planets are made of rock, earth, or a solid substance. Your other options, Jupiter, Saturn, and Uranus, are all made up of a mixture of gases.
Hope this helps!
The answer is Mars.
What is a terrestrial planet's simple definition?Terrestrial planets are Earth-like planets made up of rocks or metals with a hard surface. Terrestrial planets also have a molten heavy-metal core, few moons, and topological features such as valleys, volcanoes, and craters.
What is the difference between terrestrial and jovian planets?Terrestrial planets are smaller, closer to the Sun, and formed from the rock around a molten metal core. They have secondary atmospheres, fewer moons, and a slower spin. Jovian planets are larger, further from the Sun, and formed from gases around a solid metal and hydrogen core.
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Moving mirror M2 of a Michelson interferometer a distance of 90 μm causes 470 bright-dark-bright fringe shifts.What is the wavelength of the light?
Answer:
Wavelength, [tex]\lambda=382.9\ nm[/tex]
Explanation:
It is given that,
Distance moved by mirror in Michelson interferometer is 90 μm
Number of bright fringe shift = 470
We need to find the wavelength of the light.
For Michelson interferometer experiment,
[tex]2d=m\lambda[/tex]
here, [tex]\lambda[/tex] is the wavelength of the light
[tex]\lambda=\dfrac{2d}{m}\\\\\lambda=\dfrac{2\times 90\times 10^{-6}}{470}\\\\\lambda=3.829\times 10^{-7}\ m\\\\\lambda=382.9\ nm[/tex]
So, the wavelength of the light is 382.9 nm.
The wavelength of the light should be 382.9nm.
Calculation of the wavelength of the light:Since
Distance moved by the mirror in Michelson interferometer is 90 μm
And, Number of bright fringe shift = 470
So
we know that
2d = m*wavelength
wavelength = 2*90*10^-6/470
= 3.829*10^-7m
= 382.9nm
hence, The wavelength of the light should be 382.9nm.
Learn more about wavelength here: https://brainly.com/question/26044136
So we were working on some pulley problems but this one has kinda left me scratching my head, please help! My question is for part C :' )
Explanation:
(c) I assume we're looking for mA.
Sum of forces on B in the -y direction:
∑F = ma
mBg − T = mBa
Sum of forces on A in the +x direction:
∑F = ma
T = mAa
Substitute:
mBg − mAa = mBa
mBg − mBa = mAa
mA = mB (g − a) / a
Plug in values:
mA = (5 kg) (10 m/s² − 0.01 (10 m/s²)) / (0.01 (10 m/s²))
mA = 495 kg
The answer key seems to have a mistake. It's possible they meant mB = 1 kg, or they changed mB to 5 kg but forgot to change the answer.
Two helium-filled balloons are released simultaneously at points A and B on the x axis in an earth-based reference frame. Balloon A is to the left of balloon B. Which one of the following statements is true for an observer moving in the +x direction?
A. The observer sees balloon B released before balloon A.
B. The observer always sees the balloons released simultaneously.
C. The observer could see either balloon released first depending on her speed and the distance between A and B.
D. The observer sees balloon A released before balloon B.
Answer:
The correct answer is C
Explanation:
In this exercise you are asked to analyze the following situation: for a fixed observer, the two balloons are launched at the same time.
If the observer is mobile moving towards the positive side of axis ax we have several
possibilities when starting the movement
* the observer is to the left of the two balloons
* the observer is between the two balloons
* the observer is to the right of the two baloomls
The time it takes for the signal to arrive to know which ball goes first is
v = d / t
t = d / v
If the signal goes at the speed of light, the speed is a constant and the time will depend only on the distance, so we see that the trigger changes depending on the relative position between a given ball and the observer.
Consequently, it will be seen which comes out first, depending on the relative position with the observer.
The correct answer is C
A small loop of area 8.8 mm² is placed inside a long solenoid that has 818 turns/cm and carries a sinusoidally varying current i of amplitude 1.28 A and angular frequency 212 rad/s. The central axes of the loop and solenoid coincide.What is the amplitude of the emf induced in the loop?
Answer:
The amplitude of the induced emf is [tex]\epsilon_a = 2.45*10^{-4}\ V[/tex]
Explanation:
From the question we are told that
The area is [tex]A = 8.8 \ mm^2 = 8.8 *10^{-6} \ m[/tex]
The number f turns per cm is [tex]N = 818 \ turn/cm = 81800 \ turn /m[/tex]
The current is [tex]I = 1.28 \ A[/tex]
The angular frequency is [tex]w = 212 \ rad /s[/tex]
Generally the amplitude of the induced emf is mathematically represented as
[tex]\epsilon_a = \mu_o * N * I * w * A[/tex]
Where [tex]\mu_o[/tex] is the permeability of free space with value [tex]\mu_o = 4\pi * 10^{-7} N/A^2[/tex]
=> [tex]\epsilon_a = 4\pi * 10^{-7} * 81800 * 1.28 * 212 * 8.8*10^{-6}[/tex]
[tex]\epsilon_a = 2.45*10^{-4}\ V[/tex]
Please help :/ The same motor is used in rockets with different masses. The rockets have different accelerations. According to Newton’s second law, how is acceleration expected to change as the rocket mass increases?
Acceleration cannot be predicted based on changes in mass.
As rocket mass increases, acceleration decreases.
As rocket mass increases, acceleration increases.
There are no changes in acceleration, as it would depend on the amount of force. _
Different amounts of force are applied to the same boat over several trials, and the acceleration is measured. In a graph of acceleration versus net force, what does the slope of the graph represent?
the speed of the boat _
the mass of the boat _
the inverse of the mass of the boat _
the inverse of the speed of the boat
Answer:
1. As rocket mass increases, acceleration decreases.
2. The inverse of the mass of the boat.
Explanation:
1. Newton's second law of motion states;
F = ma
where F is the force applied, m is the mass and a is the acceleration.
Therefore, increasing the mass of a rocket increases its weight which would reduce its acceleration provided that the force is constant. Thus, as rocket mass increases, acceleration decreases.
2. The slope of the graph can be expressed as;
From Newton's second law,
F = ma
Slope = (Δa) ÷ (ΔF)
Slope = [tex]\frac{a}{F}[/tex]
⇒ [tex]\frac{1}{m}[/tex] = [tex]\frac{a}{F}[/tex]
Therefore, the slope of the graph is the reciprocal of the mass of the boat.
Answer:
As rocket mass increases, acceleration decreases.
The inverse of the mass of the boat
Drag and drop each description into the correct category
They copy the original sound
Analog signals
Digital signals
They change sound into numbers.
They reduce unwanted noise.
They may pick up unwanted noise.
They flow continuously.
They do not flow continuously
Intro
Done
Explanation:
Analog signals :
Analog signals are continuous signal. These are like wave signals that change with time period.The main disadvantage of analog signal is that it contains noise. .They flow continuously.Digital signals :
Digital signals do not flow continuously. It has finite number of values. They form in the form of numbers. They reduce unwanted noise. It is the advantage of digital signals.Answer:
Analog -
They flow continuously
They may pick up unwanted noise
They copy the original sound
Digital -
They do not flow continuously
They reduce unwanted noise.
They change sound into numbers.
Mark Brainliest PleaseTwo beams of coherent light travel different paths, arriving at point P. If the destructive interference is to occur at point P, what should be the path difference between the two waves
Answer:
Explanation:
When two coherent light beams travel different paths and arrive at a point , there will be difference in the length of path travelled by them . If this difference is zero then both will reinforce each other and their brightness will add up . Hence there will be constructive interference .
If their path difference is not zero but it is equal to odd multiple of their half wavelength like λ / 2 , 3 λ / 2 , 5 λ /2 , 7 λ /2 etc , then instead of reinforcing each other , they will destroy each other . This is called destructive interference . As a result of it , darkness will prevail at the point where they meet or interfere.
How much work did the movers do (horizontally) pushing a 46.0-kgkg crate 10.5 mm across a rough floor without acceleration, if the effective coefficient of friction was 0.50
Answer:
7.1 J
Explanation:
From the question,
Work done by the mover = work done in pushing the crate + work done against friction
W = W'+Wf................. Equation 1
W = mgd+mgμd............ Equation 2
W = mgd(1+μ)................ Equation 3
Where m = mass of the crate, g = acceleration due to gravity, d = distance, μ = coefficient of friction.
Given: m = 46 kg, d = 10.5 mm = 0.0105 m, μ = 0.5
constant: g = 9.8 m/s²
Substitute these values into equation 3
W = 46×9.8×0.0105(1+0.5)
W = 7.1 J
A 40-turn coil has a diameter of 17 cm. The coil is placed in a spatially uniform magnetic field of magnitude 0.40 T so that the face of the coil and the magnetic field are perpendicular. Find the magnitude of the emf induced in the coil (in V) if the magnetic field is reduced to zero uniformly in the following times.
Complete question:
A 40-turn coil has a diameter of 17 cm. The coil is placed in a spatially uniform magnetic field of magnitude 0.40 T so that the face of the coil and the magnetic field are perpendicular. Find the magnitude of the emf induced in the coil (in V) if the magnetic field is reduced to zero uniformly in the following times. (a) 0.10 s, (b) 1.0 s, and (c) 60 s.
Answer:
(a) E = 3.632 V
(b) E = 0.3632 V
(c) E = 6.053 mV
Explanation:
Given;
number of turn of the coil, N = 40 turn
diameter of the coil, d = 17 cm = 0.17 m
radius of the coil, r = d /2 = 0.17 /2 = 0.085 m
initial magnitude of magnetic field, B₁ = 0.4 T
final magnitude of magnetic field, B₂ = 0
The induced emf in the coil is given by;
[tex]E = -N\frac{dB}{dt} A = \frac{-NA(B_2 - B_1)}{dt} =\frac{NA(B_1-B_2)}{dt} =\frac{NAB_1}{t}[/tex]
A is area of the coil = πr² = π(0.085)² = 0.0227 m²
(a) when the time is 0.1 s
[tex]E= \frac{40*0.0227*0.4}{0.1} = 3.632 \ V[/tex]
(b) when the time is 1 s
[tex]E = \frac{40*0.0227*0.4}{1} \\\\E = 0.3632 \ V[/tex]
(c) when the time is 60 s
[tex]E = \frac{40*0.0227*0.4}{60} \\\\E = 6.053 \ mV[/tex]
What is charging by contact
Answer:
Charging by contact is when the charged object is brought near but never contacted to the object being charged
Explanation:
Kelly is driving a car with a mass of 800 kilograms in a south direction with a speed of 18 meters/second. Dominic is driving a truck with a mass of 1500 kilograms with a velocity of 15 meters/second to the east. They undergo perfectly inelastic collision. What is the magnitude of the final momentum of both the truck and the car.
Answer:
Approximately [tex]2.7\times 10^{4}\; \rm kg \cdot m \cdot s^{-1}[/tex].
Explanation:
The two colliding objects would be stuck to each other if the collision is perfectly inelastic. While kinetic energy is conserved only in elastic collisions, momentum is conserved in all types of collisions. Therefore, the momentum of the truck and the car right after the collision will be equal to the vector sum of their momentum right before the collision.
Momentum of the car right before the collision:
[tex]\vec{p}(\text{car, before}) = m \cdot \vec{v} = 800\; \rm kg \times 18\; \rm m \cdot s^{-1}= 14400\; \rm kg \cdot m \cdot s^{-1}[/tex].
Momentum of the truck right before the collision:
[tex]\vec{p}(\text{truck, before}) = m \cdot \vec{v} = 1500\; \rm kg \times 15 \; \rm m \cdot s^{-1} = 22500\; \rm kg \cdot m \cdot s^{-1}[/tex].
Note that these two momentum are perpendicular to each other. The magnitude of their vector sum should be found using the Pythagorean theorem:
[tex]\begin{aligned}&\left|\vec{p}(\text{sum, before})\right| \\ &= \left|\vec{p}(\text{car, before}) + \vec{p}(\text{truck, before})\right| \\ &= \left(\sqrt{14400^2 + 22500^2}\right)\; \rm kg \cdot m \cdot s^{-1} \approx 2.7\times 10^{4}\; \rm kg \cdot m \cdot s^{-1} \end{aligned}[/tex].
Because momentum is conserved, the sum of the momentum of the car and the truck right after the collision should be equal to the sum right before the collision. In other words:
[tex]\vec{p}(\text{sum, after}) = \vec{p}(\text{sum, before})[/tex].
Therefore:
[tex]\left|\vec{p}(\text{sum, after})\right| = \left|\vec{p}(\text{sum, before})\right| \approx 2.7 \times 10^{4}\; \rm kg \cdot m \cdot s^{-1}[/tex].