Answer:
d) 105 s
Explanation:
Given the following data;
Distance A (length of train) = 100 m
Velocity = 72 km/h to meters per seconds = 72 * 1000)/3600 = 72000/3600 = 20 m/s
To find the time;
Time = distance/speed
Time = 100/20
Time = 5 seconds.
II. When the distance (bridge) is 2km;
Distance B = 2km = 2*1000 = 2000 meters
Time = distance/speed
Time = 2000/20
Time = 100 seconds
Therefore, total time = 5 + 100 = 105 seconds
Una carga de 4 nC es transportada desde el suelo hasta la superficie de una esfera cargada con un trabajo de 7 X 10-5 j. Determinar el potencial eléctrico de la esfera
Respuesta:
2 × 10⁴ V
Explicación:
Paso 1: Información provista
Carga transportada (q): 4 nCTrabajo realizado (W): 7 × 10⁻⁵ JPaso 2: Convertir q a Coulomb
Usaremos el factor de conversión 1 C = 10⁹ nC.
4 nC × 1 C/10⁹ nC = 4 × 10⁻⁹ C
Paso 3: Calcular el potencial eléctrico (V) de la esfera
Usaremos la siguiente fórmula.
V = W/q
V = 7 × 10⁻⁵ J/4 × 10⁻⁹ C = 2 × 10⁴ V
A child drops a bouncy ball. Each time it bounces, it reaches a lower height until it eventually
stops. Describe the energy transfers and explain why the ball lowered in height
Answer:
the ball's was lowered because of the gravitational force and because of the friction force's
Which of these statements explains why we have day and night? [1] The Earth orbits the Sun once a day The Sun orbits the Earth once a day. The Sun spins on its axis once a day. The Earth spins on its axis once a day.
Answer:
The Earth spins on its axis once a day.
Explanation:
In simple words,The Earth revolves on its axis once every 24 hours and circles the sun once every 365 days. The Earth's rotation on its axis, not its orbit throughout the sun causes day as well as night. The word 'one day' refers to the period it requires the Earth to spin entirely on its axis, which involves both day as well as night.
How does the motion of the molecules change when you increase the temperature
Answer:
They speed up as temperature increases.
Explanation:
As temperatures increases within a molecule the particles will speed up.
Use Newton's second law of motion and a free-body diagram to...
1. ...calculate the normal force acting upon a 50-kg passenger who accelerates upward at a rate of 3.0 m/s/s.
2. ...calculate the normal force acting upon a 50-kg passenger who accelerates downward at a rate of 3.0 m/s/s.
Please don't put any links or I will report you.
who is the first physicist and what did he invented?
Answer:
hippocrates
I guess..........
True or False. The Magnitude of the induced voltage in a coil of wire depends on how quickly the magnetic flux through the coil of wire changes.
Answer:
Yes, its true
Explanation:
hdheheishdhieijzuwhs
Answer: yes its true
Explanation:
nmo
Bajo la acción del viento una puerta gira un ángulo de 90° en 5 s. Calcular su velocidad angular y la velocidad lineal de los puntos del borde
si el ancho de la puerta es de 50 cm. R. 0,314 rad/s, 0,157 m/s.
A specified volume of space contains an electric field for which the magnitude is given by E=E0cos(ωt). Suppose that E0 = 20 V/m and ω = 1.0 × 107 s−1. What is the maximum displacement current through a 0.40 m2 cross-sectional area of this volume?
Answer: [tex]0.708\ mA[/tex]
Explanation:
Given
[tex]E_o=20\ V/m[/tex]
[tex]\omega =10^7\ s^{-1}[/tex]
Cross-sectional area [tex]A=0.40\ m^2[/tex]
Current density is given by
[tex]J=\epsilon_o \dfrac{dE}{dt}[/tex]
Displacement current
[tex]\Rightarrow I=JA\\\Rightarrow I=8.854\times 10^{-12}\times 20\times 10^7\times 0.4\\\Rightarrow I=0.708\times 10^{-3}\ A[/tex]
The required value of the maximum displacement current of the given space is [tex]7.08 \times 10^{-4} \;\rm A[/tex].
Given data:
The intensity of electric field is, [tex]E_{0}=20 \;\rm V/m[/tex].
The angular frequency of electric field is, [tex]\omega=1.0 \times 10^{7} \;\rm s^{-1}[/tex].
The cross-sectional area of space is, [tex]A =0.40 \;\rm m^{2}[/tex].
In the given problem, the instantaneous electric field is given by [tex]E = E_{0} \times cos(\omega t)[/tex]
So, the expression for the current density is,
[tex]J= \epsilon_{0} \times \dfrac{dE}{dt}[/tex]
Here, [tex]\epsilon_{0}[/tex] is the permittivity of free space. Solving as,
[tex]J= \epsilon_{0} \times \dfrac{d(E_{0} \times cos(\omega t))}{dt}\\\\J= -\epsilon_{0} \times E_{0} \times \omega \times sin(\omega t)[/tex]
And the expression for the maximum displacement current is,
[tex]I = J \times A[/tex]
And the maximum displacement current is possible only when, J is positive and J will be positive for [tex]sin(\omega t)=-1[/tex].
Then solving as,
[tex]I = (-\epsilon_{0} \times E_{0} \times \omega \times sin(\omega t)) \times A\\\\I = (-8.85 \times 10^{-12} \times 20 \times (1.0 \times 10^{7}) \times (-1)) \times 0.40\\\\I = 7.08 \times 10^{-4} \;\rm A[/tex]
Thus, we can conclude that the required value of the maximum displacement current of the given space is [tex]7.08 \times 10^{-4} \;\rm A[/tex].
Learn more about the displacement current here:
https://brainly.com/question/20344850
Matter cant be created or destroyed
true
false
Answer: True
no matter can be created nor destroyed in any process. if something is burned, made in a compound or anything like that all matter is still the same amount from beginning to end.
Explanation:
A 74.2 kg teenager slides down a frictionless slide that has an angle of inclination of 38˚. What is the magnitude of the acceleration of the teenager down the slide?
Answer:
Explanation:
This is one-dimensional motion on an incline which makes it so much more funner :/
The equation for this is
w*sinθ - f = ma which is just a fancy version of Newton's second law that says that the sum of the forces acting on an object are equal to that object's mass times its acceleration.
w is the weight of the teen which is also the normal force, [tex]F_n[/tex]. Therefore,
[tex]w=F_n=mg[/tex] where m is mass and g is gravity:
[tex]w=F_n=(74.2)(9.8)[/tex] and we need 2 sig figs for this since there are 2 in 9.8:
w = 730N
Since there is no friction in this problem, the value for f, frictional force, is 0, making our job a bit shorter. Filling in the main equation:
730sin38 - 0 = 74.2a
Since the left side is subtraction and we will eventually have to divide, and the rules for subtraction/addition are different from those for multiplication/division, we will have to subtract first, get the correct number of sig figs for that difference, and then divide, following the rules for division.
730sin38 will have 2 sig figs which is 450. Now
450 - 0 = 74.2a and
450 = 74.2a and divide to 2 sig figs:
a = 6.1 m/s/s
skater spins over a point at a speed of 3.0 rotations per second then the momentum of inertia is 0.60 kg.M2, what is its angular momentum?
Answer:
[tex]L=11.3\ kg-m^2/s[/tex]
Explanation:
Given that,
Angular speed of a skater, [tex]\omega=3\ rot/s=18.84\ rad/s[/tex]
The moment of inertia of the skater, I = 0.6 kg-m²
We need to find the angular momentum of the skater. The formula for the angular momentum of the skater is given by :
[tex]L=I\omega[/tex]
Substitute all the values,
[tex]L=0.6\times 18.84\\\\L=11.3\ kg-m^2/s[/tex]
So, its angular momentum is equal to [tex]11.3\ kg-m^2/s[/tex].
An electromagnet is a device that uses an electric current to produce a magnetic field.
Electromagnets are typically composed of a piece of metal wrapped with wire and connected to a battery. The battery provides the electric current, and the loops or coils of wire enhance the magnetic field. The more loops there are, the stronger the magnetic field.
When electric current flows through the electromagnet, the metal core becomes magnetized, so it possesses a north pole and a south pole.
Motors place electromagnets inside of permanent magnets as shown below.
However, motors are designed so that the polarity of the electromagnet constantly flips. That is, the north pole becomes the south pole, and the south pole becomes the north pole, every time the electromagnet turns 180 degrees.
Why is it designed this way?
A.
to conserve the energy in the battery
B.
to constantly polarize the field magnet
C.
so the electromagnet will continuously turn
D.
so the magnetic field will get stronger
The reason why motors are designed so that the polarity of the electromagnet constantly flips.is
C. so the electromagnet will continuously turn
Why is motor designed that wayThe reason motors are designed so that the polarity of the electromagnet constantly flips is to continuously turn the electromagnet. This allows the motor to rotate continuously, rather than becoming stuck in one position.
The flipping of the polarity causes the electromagnet to attract and repel from the permanent magnets, creating a rotating motion.
Therefore, the correct answer is C.
Learn more about motors at:
https://brainly.com/question/18619348
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Which is closest to the Earth?
A. Moon
B. Sun
C. Mars
D. Venus
Answer:
A. Moon
Explanation:
The Moon is hundreds of thousands of miles away from the Earth while the other options are hundreds of millions of miles away.
If a body is thrown up with an initial velocity 'u' and covers a maximum height of 'h' , then 'h' is equal to u²/2g
Explain in detail.
Answer:
1/2 m u^2 initial Kinetic Energy of body
m g h Potential Energy body attains as it rises to height
1/2 m u^2 = m g h conversion of KE to PE
h = u^2 / ( 2 g)
How is it possible a plant can sustain itself for 70 years locked inside a jar ?
Answer:
If you are talking about the experiment in which mouse and plants are kept in a closed glass jar in sunlight so in that case, they both survive because the CO2 released by the respiration of mouse is being utilized by the plants and fixed ( phosynthesis) and O2 is released as by product, which is taken by the mouse for respiration.
If you're the white mouse, what will you do in order for you to survive
Answer:
If I was the white mouse, I would either find somewhere to hide that matches my fur color to camoflouge with or dig into the dirt so less visible.
To find white colour habitat.
What will I do for my survival?If I was the white mouse, I would find white colour place for living because in that white colour the predators can't see me and i will be safe from them so we can conclude that finding white colour habitat is the best choice to safe myself.
Learn more about survive here: https://brainly.com/question/24323334
Our entire ______ _____
is built in the backbone of metals.
Answer:
modern world
Explanation:
An object has a mass of 10grams and a volume of 20m3. what is the density of the object
Explanation:
density = mass/ volume
in the question the mass is given in grams so will convert it into kg,
10 g = 0.01 kg
density= 0.01/ 20 = 1 / 2000 = 0.005 kg/m^3
A 1200 kg car accelerats from reat to 10.0 m/s in a time of 4.50 seconds. Calculate the force that thr car's tires exerted on the road.
Answer:
2667 N
Explanation:
Method 1: ImpulseWe can solve this problem by using the impulse formula.
FΔt = mΔv Δt = time interval, m = mass of the car (kg), Δv = change in velocityWe have three known variables, so we can solve for the fourth: F.
Divide Δt from both sides to isolate F.
F = (mΔv)/ΔtSubstitute known values into the equation.
F = [(1200 kg)(10 m/s - 0 m/s)] / 4.5 s F = [(1200)(10)]/4.5 F = 12000/4.5 F = 2666.666667 NThe force that the car's tires exert on the road is 2667 N.
Method 2: Newton's Second LawThe force that the car's tires exert on the road is equivalent to the force that the road exerts on the car due to Newton's Third Law of Motion.
We can calculate the force that the car's tires exert on the road by using the formula F = ma, which was derived from Newton's Second Law of Motion.
F = ma F = force exerted on the car, m = mass of the car (kg), a = acceleration of the car (m/s²)We are given the mass of the car, velocity of the car, and the time in which it accelerated.
We can use this equation for acceleration:
a = Δv/Δt Δv = final velocity - initial velocity (change in velocity), Δt = time intervalThe car started from rest, meaning it had an initial velocity of 0 m/s. Its final velocity was 10 m/s. The time that it took for the car to go from 0 m/s to 10 m/s was 4.5 seconds.
a = (10 m/s - 0 m/s) / 4.50 s a = 10/4.5 a = 2.222... m/s²Now we have two known variables, mass and acceleration. We can solve for the force exerted on the car (and thus, the force the car exerts on the road) using the formula F = ma.
F = ma F = (1200 kg)(2.222... m/s²) F = 1200 · 2.222...F = 2666.666667 NThe force that the car's tires exert on the road is 2667 N.
help.....please science
Answer:
please mark me brainliest
Explanation:
ohm
The SI-derived unit of electric resistance is the ohm, which is defined as a volt per ampere.
Answer:
I cant see that
a vehicle is moving with 20m/s towards the east and another is moving 15m/s towards the west
Answer:
5 m/s
Explanation:
Given that,
A vehicle is moving with 20m/s towards the east and another is moving 15m/s towards the west.
It is assumed to find the resultant velocity of the vehicle. Let east side is positive and west is negative. So,
[tex]v=v_1+v_2\\\\=20+(-15)\\\\=5\ m/s[/tex]
Hence, the resultant velocity of the vehicle is equal to 5 m/s.
A step down transformer has a primary coil consisting of 700 tons and a secondary coil consisting of 300 times. What is the potential difference in the second circuit, if the primary coil is supplied with an effective AC potential difference of 110 V?
Answer is 47.14 v
by the relation
[tex]\frac{V out}{V in } = \frac{N secondary}{N primary }[/tex]
The average mass of an adult American female is 75 kilograms. What is the weight of
the average female in pounds?
Answer:
with 75kg --> 165.35 pound(lb)
Explanation:
[tex] \frac{75}{0.45359237} [/tex]
A rigid body of moment of inertia 0.5 kg.M^2 rotates with 2 RPM. How much torque is needed to increase the rotation to 10 RPM in 5 seconds.
Answer:
T = 0.084 Nm
Explanation:
First, we will calculate the angular acceleration:
[tex]\alpha = \frac{\omega_f - \omega_i}{t}[/tex]
where,
α = angular acceleration = ?
ωf = final angular speed = (10 RPM)(2π rad/1 rev)(1 min/60 s) = 1.05 rad/s
ωi = initial angular speed = (2 RPM)(2π rad/1 rev)(1 min/60 s) = 0.21 rad/s
t = time = 5 s
Therefore,
[tex]\alpha = \frac{1.05\rad/s - 0.21\ rad/s}{5\ s}\\\\\alpha = 0.168\ rad/s^2[/tex]
Now, for the torque:
[tex]T = I\alpha[/tex]
where,
T = torque = ?
I = moment of inertia = 0.5 kg.m²
Therefore,
[tex]T = (0.5\ kg.m^2)(0.168\ rad/s^2)\\[/tex]
T = 0.084 Nm
define one ampere current electricity
2. Give at least 2 major roles of mining in our lives.
Answer:
Mined materials are needed to construct roads and hospitals, to build automobiles and houses, to make computers and satellites, to generate electricity, and to provide the many other goods and services that consumers enjoy.
Explanation:
Why does the golf ball sink in
water, while the beach ball
floats?
A- The beach ball weighs less than
the golf ball
B- The golf ball has a higher density
than the beach ball
C- The beach ball has a higher
density than the golf ball
D- The golf ball has more mass than
the beach ball
Which beach balls have potential energy and not kinetic energy?
Answer:
Beach ball 4
Explanation:
it is because, Potential Energy = M G H
P(e) directly proportional to H.
if H increase then P energy also increases
How does refraction allow thin convex lenses to work?
Answer:
https://www.khanacademy.org/science/physics/geometric-optics/lenses/v/convex-lenses
Explanation:
Here is a link to a video to tell you about this.
