Explanation:
eff = m.a/ v.r
m.a = L /E
30/ 20
= 1. 5
if the diameter of a wire were decreased it's electrical resistance would
Base your answers to questions 4 and 5 on the informa- tion below
A lightweight sphere hangs by an insulating thread. A student wishes to determine if the sphere is neutral or electrostatically charged. She has a negatively charged hard rubber rod and a positively charged glass rod. She does not touch the sphere with the rods, but runs tests by bringing them near the sphere one at a time.
4. Describe the test result that would prove that the sphere is neutral
5. Describe the test result that would prove that the sphere is positively charged.
If the sphere is positively charged, the positive rod is repelled by the sphere while the negative rod is attracted by the sphere.
What is an electrical charge?An electrical charge can be positive or negative. From the laws of electrostatics, unlike charges attract while like charges repel. As such the effect observed when the rods are individually brought near the sphere will decide the charge on the sphere.
If the sphere is neutral, there is no effect observed when each rod is brought near the sphere. If the sphere is positively charged, the positive rod is repelled by the sphere while the negative rod is attracted by the sphere.
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The gravitational force between the sun and every object in the solar system helps keep each object in its own unique orbit around the sun. Lesson 3. 03 Question 2 options: True False.
Answer:
True
Explanation:
i did the Quiz
Answer:
A: true
Explanation:
I took the test its right, trust me I got 100%
When you double the voltage across a certain material or device, you observe that the current increases by a factor of 3.
Explanation:
The current which flows through the circuit is dependent on the resistance of the material/device. Given by the equation U=RI
If U becomes 2U
And I becomes 3 I
then R×2=3
R=3/2=1.5 Ω
Hope this answers your question?
Which element is magnetic?
O calcium
O chromium
O carbon
O cobalt
Answer: D. Cobalt
Explanation: Cobalt has excellent magnetic properties so it is D. Cobalt.
The element which has magnetic properties from the given list of elements would be cobalt , therefore the correct answer is option C.
What are metalloids?The elements of the periodic tables that behave as metals, as well as the nonmetal in some chemical or physical aspects, are known as metalloids. Some examples of metalloids are Boron , silicon , germanium, arsenic , antimony , tellurium , etc.
As given in the problem we have to find out the element which possesses the magnetic properties from the given list ,
Calcium belongs to group 2 of the periodic table and nonmagnetic element . Similarly , carbon is a nonmagnetic material .
Thus , the element which has magnetic properties from the given list of elements would be cobalt, therefore the correct answer is option C .
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What is the purpose of Physical Science?
to improve technology that affects our quality of life
to explain and predict phenomena that affect our view of the universe
all answers are true
to answer everyday questions
WHOEVER ANSWERS FIRST GET BRAINLIEST
You look down an old well, cannot see the bottom, and mutter to yourself "Oh well!". In order to estimate the depth of the well, you then drop five stones and record the time for each to impact: 2.19s, 2.30s, 2.26s, 2.29s, and 2.27s. What is the best estimate of the depth of the well? Explain your reasoning.
Answer:
The best estimate of the depth of the well is 2.3 sec.
Explanation:
Given that,
Record time,
[tex]t_{1}=2.19\ sec[/tex]
[tex]t_{2}=2.30\ sec[/tex]
[tex]t_{3}=2.26\ sec[/tex]
[tex]t_{4}=2.29\ sec[/tex]
[tex]t_{5}=2.27\ sec[/tex]
We need to find the best estimate of the depth of the well
According to record time,
We can write of the record time
[tex]t_{1}=2.19\approx 2.2\ sec[/tex]
[tex]t_{2}=2.30\approx 2.3\ sec[/tex]
[tex]t_{3}=2.26\approx 2.3\ sec[/tex]
[tex]t_{4}=2.29\approx 2.3\ sec[/tex]
[tex]t_{5}=2.27\approx 2.3\ sec[/tex]
Here, all time is nearest 2.3 sec.
So, we can say that the best estimate of the depth of the well is 2.3 sec.
Hence, The best estimate of the depth of the well is 2.3 sec.
Suppose the line on a distance-versus-time graph and the line on a speed-versus-time graph are both slanted straight lines going through the origin. Can the two graphs be displaying the motion of the same object? Explain.
The two given graphs can be displaying the motion of the different objects. As the distance-versus-time graph shows the speed is constant while the speed-versus-time graph shows the uniform acceleration motion.
What is uniform acceleration motion?A uniformly accelerated motion is one in which the acceleration of the object throughout the motion is uniform. When an object is moving in a straight line with an increase in velocity at equal intervals of time, then we can say that object has uniform acceleration.
Projectile motion is an example of motion in a plane with uniform acceleration. The only acceleration acting on the particle is the acceleration due to gravity (g) in the case of projectile motion. Since there is no acceleration in the horizontal direction, the velocity in the x-direction will be constant.
In the distance-versus-time graph, the straight line passing through the origin shows the increase in the distance at equal intervals of time. So, the speed of the object will be constant.
The speed-versus-time graph shows the increase in the speed at equal intervals of time. So, the acceleration of the object will be constant. So this is the graph of the motion of a different object.
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Assuming that no outside forces are acting on ma or mb, which of the following expression BEST represents the speed, v' of the masses after the collision?
Answer: B
Explanation:
The conservation of momentum states that the initial momentum of the system must equal the final momentum of the system. Our system in this case is the two colliding objects and ONLY the two colliding objects. Initially, our system had mass 1 moving towards a stationary mass 2. The stationary mass has a velocity of 0m/s and therefore has no momentum. The initial momentum would then be:
[tex]p_i=m_1v_1_i+m_2v_2_i[/tex]
[tex]p_i=m_1v_1_i[/tex]
The final momentum depends on what type of collision occurred. This case is the simplest type of collision, when the objects stick to each other and act as one. Since the objects move together, their velocity must be the exact same. Our final momentum looks like:
[tex]p_f=m_1v_f+m_2v_f[/tex]
[tex]p_f=v_f(m_1+m_2)[/tex]
Setting the initial momentum equal to the final momentum:
[tex]p_i=p_f[/tex]
[tex]m_1v_1_i=v_f(m_1+m_2)[/tex]
Solving the final velocity:
[tex]v_f=m_1v_1_i/(m_1+m_2)[/tex]
Which matches answer B
Which is the best example of a scientific discovery resulting from new technology?
the discovery that elements can be grouped in a table on the basis of their properties
the discovery of atomic structure which led to the development of an electron microscope
the discovery of the structure of DNA, which occurred as the result of an X-ray image of a DNA molecule
the discovery that plant pigments can be separated and identified by using paper and a solvent
third
Explanation:
i think so because finding structure of dna can help a lot for well being of human being
A train accelerates from 23m/s to 190m/s in 54 seconds. What was its acceleration?
Answer:
Use the method on the image and solve it.
The train is accelerating with an initial velocity of 23 m/s, a final velocity of 190 m/s in the time period of 54 seconds, then the acceleration will be 3.09 m/s².
What is velocity?Velocity is the measurement of a particle's or object's displacement with relation to time. The recognized unit of magnitude for velocity is the meter per second (m/s) (also known as speed).
There are several ways to show a velocity vector's direction, depending on how many dimensions are provided.
The given values in the question are,
Initial velocity, u = 23 m/s
Final velocity, v = 190 m/s and,
Time, t =54 seconds.
By putting the formula of the equation of motion :
v = u + at
190 = 23 + (a)(54)
a = 167/54
a = 3.09 m/s².
Hence, the acceleration of the train is equal to 3.09 m/s².
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Which of the following are correct units for acceleration? Chooses all that are correct.
m/s/s
km/hr/hr
m/s
s
km/hr/s
m
m/hr
4. A body with an initial velocity of 8 m/s moves with a constant acceleration and travels 640m in 40 seconds. What is the acceleration of the body?
Answer:
a= 9.81 s
Explanation:
vi= 8m/s
a= -9.81 m/s
d= 640m
t= 40s
1. Find final velocity
vf= vi +a(t)
vf= 8m/s + -9.81m/s x 40s
vf = -384.4 m/s
acceleration= change in velocity/ change in time
a= -384.4- 8= -392.4/ 40s = 9.81s
a= 9.81 m/s
Hopefully this helps and is correct! Much love ❤️
3. A boy does 15 Joules of work to push a cart covering 2.5 meters. How much force did he use?
Given:
Solve For:
Solution:
Answer: 6 N
Explanation: W (WORK) = 15 JOULES
S (DISTANCE) = 2.5 m
F (FORCE) = ?
BY USING FORmULA OF WORK DONE
W = F.S
F =W/S
F = 15/2.5
F = 6 N
A train is moving with a velocity of 20 m/s. when the brakes are applied the acceleration is reduced to -0.6 m/s².calculate the distance covered by the train before coming to rest
Answer:
x = 333.33 [m]
Explanation:
To solve this problem we must use the following kinematics equation.
[tex]v_{f}^{2} = v_{i}^{2}-(2*a*x)[/tex]
where:
Vf = final velocity = 0
Vi = initial velocity = 20 [m/s]
a = desacceleration = 0.6 [m/s^2]
x = distance [m]
Note: the final speed is zero as the body finishes its movement.
Now replacing:
0 = (20)^2 - (2*0.6*x)
1.2*x = 400
x = 333.33 [m]
The wheel is composed of a 10-kg hoop stiffened by four thin spokes, each with a mass of 2 kg. A hori- zontal force of 40 N is applied to the wheel initially at rest. Calculate the angular velocity of the wheel after its center has moved 3 m. Friction is sufficient to prevent slipping.
For a wheel composed of a 10-kg hoop stiffened by four thin spokes and each with a mass of 2 kg, the angular velocity is mathematically given as
w=1.165 rad/s
What is the angular velocity of the wheel after its center has moved 3 m.?Generally, the equation for the angular velocity is mathematically given as
[tex]V = \sqrt{(F * r/m)[/tex]
Therefore
[tex]V= \sqrt{(40 x 0.3 / 98.1)[/tex]
V= 0.35 m/s
Where
w=v/r
w= 0.35/0.3
w=1.165 rad/s
In conclusion, the angular velocity is
w=1.165 rad/s
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A jet takes off from an aircraft carrier starting from rest and travels 93 m [fwd] in 1.2 s when being pushed by the catapult. What is its final velocity at takeoff?
The final velocity of the Jet from the takeoff is 15.5 m/s.
Final velocity of the Jet
The final velocity of the jet is determine by applying second kinematic equation, using the principle of average velocity as shown below.
s = (u + v)t/2
where;
s is the distance traveled by the Jetu is the initial velocity of the jetv is the final velocity of the jett is the time of motions = (0 + v)t/2
2s = vt
v = 2s/t
v = (2 x 9.3) /1.2
v = 15.5 m/s
Thus, the final velocity of the Jet from the takeoff is 15.5 m/s.
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what is reference frame
Answer: A reference frame is simply a perspective, context, or point of view. In physics that typically means physical space time coordinates, in the social sciences it takes on a slightly different meaning. In both fields, everything is relative to the point of view of the observer ( relativity ).
Explanation:
Answer:
In physics, a frame of reference consists of an abstract coordinate system and the set of physical reference points that uniquely fix the coordinate system and standardize measurements within that frame. For n dimensions, n + 1 reference points are sufficient to fully define a reference frame.
Explanation:
Also called reference frame. Physics. a framework that is used for the observation and mathematical description of physical phenomena and the formulation of physical laws, usually consisting of an observer, a coordinate system, and a clock or clocks assigning times at positions with respect to the coordinate system.
Reference frame, also called frame of reference, in dynamics, system of graduated lines symbolically attached to a body that serve to describe the position of points relative to the body.
Choosing a frame of reference requires deciding where the object's initial position is and which direction will be considered positive. ... Frames of reference are particularly important when describing an object's displacement. Displacement is the change in position of an object relative to its reference frame.
Actually, frames of references are classified into two types depending upon how they are moving. Those two types are called inertial and non-inertial frames of reference. An inertial frame of reference has no acceleration. The law of inertial holds in such a frame; no fictitious forces arise.
You drop your frozen rock from a green bridge. The frozen rock starts from rest (initial velocity = 0ms). The rock takes 4.3s to hit the water below. The acceleration due to gravity on Earth is 9.8m\s2 s 2 downward. What is the frozen rocks velocity after 1.5 seconds? vf = vi + at
Answer:
The velocity of the frozen rock at [tex]t = 1.5\,s[/tex] is -14.711 meters per second.
Explanation:
The frozen rock experiments a free fall, which is a type of uniform accelerated motion due to gravity and air viscosity and earth's rotation effect are neglected. In this case, we need to find the final velocity ([tex]v[/tex]), measured in meters per second, of the frozen rock at given instant and whose kinematic formula is:
[tex]v = v_{o} + g\cdot t[/tex] (Eq. 1)
Where:
[tex]v_{o}[/tex] - Initial velocity, measured in meters per second.
[tex]g[/tex] - Gravity acceleration, measured in meters per square second.
[tex]t[/tex] - Time, measured in seconds.
If we get that [tex]v_{o} = 0\,\frac{m}{s}[/tex], [tex]g = -9.807\,\frac{m}{s^{2}}[/tex] and [tex]1.5\,s[/tex], then final velocity is:
[tex]v = 0\,\frac{m}{s}+\left(-9.807\,\frac{m}{s^{2}} \right) \cdot (1.5\,s)[/tex]
[tex]v = -14.711\,\frac{m}{s}[/tex]
The velocity of the frozen rock at [tex]t = 1.5\,s[/tex] is -14.711 meters per second.
A car moves at 72 km/h and car B moves at 90 km/h, approach each other. A car honked with a frequency of 650 Hz. If the speed of the sound waves in the air is 350 m/s, then what is the frequency of sound heard by the driver of car B from car A?
Givens:
Equation:
Solution:
Unit:
Substitution:
The frequency of the sound heard by the driver of car B from car A is mathematically given as
F=738.6hz
What is the frequency of the sound heard by the driver of car B from car A?Question Parameters:
A car moves at 72 km/h and car B moves at 90 km/h, approaching each other. A car honked with a frequency of 650 Hz
the speed of the sound waves in the air is 350 m/s,
Generally, the equation for the Frequency is mathematically given as
[tex]F=f'(\frac{v+vob}{v-vsource})[/tex]
Therefore
[tex]F=650(\frac{350+25}{350-20})[/tex]
F=738.6hz
In conclusion, the frequency of the sound is
F=738.6hz
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How much heat is absorbed by 0.050kg of lead when it is heated from 20°C to 100°C?
Answer:
Mass of substance m = 0.050Kg
Initial Temperature T₁ = 20°C
Final Temperature T₂ = 100°C
we have to calculate the heat absórbed by the lead .
Since spècific heat of lead is not gíven so we will take spècific heat of lead 128 J/kg°C
[tex] \diamond \bf \: Q\: = m \times c( \Delta \: t) [/tex]Put the given value
[tex]\sf \longrightarrow \: Q = 0.050 \times 128 \times (100 - 20) \\ \\ \\ \sf \longrightarrow \: Q = 0.050 \times 128 \times (80) \\ \\ \\ \sf \longrightarrow \: Q = 6.4 \times 80 \\ \\ \\ \sf \longrightarrow \: Q = 512 \: joules[/tex]
Therefore,
Heat absórbed by the lead is 512 Joules.3 A spider runs along the top of a wall at a speed of 0.24 m/s. How far will it run
in 5 s?
Answer:
The answer is 1.2 mExplanation:
In order to find the distance covered we use the formula
distance = velocity × timeFrom the question
velocity = 0.24 m/s
time = 5 s
We have
distance = 0.24 × 5
We have the final answer as
1.2 mHope this helps you
lf an object's velocity changes from 25 meters per second to 15 meters per second in 2.0 seconds, the magnitude of the object's acceleration is
Answer:
-5 m/s^2
Explanation:
[tex]acceleration = \frac{change \: in \: velocity}{time} \\ \\ = \frac{15 - 25}{2} \\ \\ = \frac{ - 10}{2} \\ \\ = - 5 \: m {s}^{ - 2} \\ \\ negative \: sign \: represents \: that \: \\ object \: is \: slowing \: down.[/tex]
Explanation:
Acceleration is the change in velocity over time.
a = Δv / Δt
a = (15 m/s − 25 m/s) / 2.0 s
a = -5.0 m/s²
The magnitude of the acceleration is 5.0 m/s².
Which material is typically used as a thermal insulator?
copper
foam
ceramic
aluminum
Answer:
Foam
Explanation:
Took the test
The materials that are typically used as a thermal insulator are foam and ceramic.
What is meant by thermal insulator ?The object that blocks the heat from transferring from one area to another is referred to as a thermal insulator.
Here,
The reduction of heat transfer (the movement of thermal energy between objects of different temperatures) between objects in thermal contact or within the impact of radiation is known as thermal insulation. In addition to using the right object forms and materials, specially engineered technologies or processes can also be used to provide thermal insulation.
The broad term for thermal preserving and heat insulating materials is thermal insulating materials, often known as materials or material complexes that appear to be resistant to thermal currents. Heat insulation prevents heat from leaving whereas thermal preservation stops heat from escaping or spreading.
Hence,
The materials that are typically used as a thermal insulator are foam and ceramic.
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If the speed of a wave is
150m/s and its frequency is
2Hz, what is its wavelenght?
Answer:
wavelength =75m
using v=fΠ
where Π is wavelength
Find the weight (W) of a 60 kg table.
g on earth is
9.8 m/s2
Explanation:
Weight = Fg = mg = (60 kg)*(9.8 m/s2) = 588 N.
You are riding in a vehicle with a coffee cup on the dashboard while traveling 30 km/h. The vehicle makes a sudden stop to avoid hitting the car that has
stopped in front of it.
Answer:
It would move forward.
Explanation:
True or False:
If an object is more dense than
water it will float.
Plzzzz Help me
Answer:
it will sink because object that have less they float not more
Answer:
it will sink here's why
Explanation: The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is placed in. An object will sink if it is more dense than the liquid it is placed in.
2. A train travels at a speed of 30mph and travel a distance of 240 miles. How
long did it take the train to complete it’s journey?
Answer:
Speed = Distance/ Time
Time= Distance/ Speed
=240/30= 8 hours
Explanation:
Hope this helps u
Crown me as brainliest:)
How does the balls potential energy relate to the amount of work needed to place the ball on the 2 m shelf
Potential Energy of the ball = Amount of work needed to place the ball on the 2 m shelf = [tex]19.62 \times m = f(mass \; of\; balls )[/tex]
By the definition of work
[tex]Work = F.ds......(1)[/tex]
Let us consider a ball having mass = [tex]m[/tex]
Weight of the ball = [tex]mg[/tex]
Equation (1) defines Work.
If the work is to be done against acceleration due to gravity of earth
then the work needed to keep the ball at height [tex]h[/tex] is given by equation (2)
[tex]Work = mg\times h[/tex]......... (2)
Also the Potential Energy of mass m kept at height h is given by equation (3)
[tex]Potential \; Energy = mgh[/tex]......(3)
given
The height of the shelf = 2 m
So From Equation (1) and (2) we get
[tex]Work = Potetial Energy = 19.62\times m \; Joule[/tex]
So both Work and Potential Energy are equal in this case and function of masses of the balls.
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