Answer:
the war of currents is
Explanation:
The war of currents was a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s.
Answer:
a series of events surrounding the introduction of competing electric power transmission systems in the late 1880s and early 1890s
Explanation:
11. How fast will a pebble be traveling 3 seconds after being dropped? (g = 9.8 m/s2)
A.-9.8 m/s
B.29.4 m/s
C.9.8 m/s2
D.29.4 m/s
what energy transfer will a stretched rubber band have when let go
Answer:
when the rubber band is realeased the potential energy is quickly converted to kinetic energy this is equal to one mass of the the rubber band multiplied by its velocity( in meters per second)
Someone help me please it’s urgent
A student builds an electromagnet using a battery, an iron nail, and some insulated wire. The wire is wrapped around the nail 50 times, then connected to the
battery. What changes could the student make to increase the strength of the electromagnet?
1. wrap more wire around the nail
2. increase the voltage of the battery
3. use a switch to turn the electromagnetic on and off
4. increase the size of the nail
A. 1 and 2
B. 2 and 4
C. 1,2 and 4
D. 1,2,and 3
Answer:
a
Explanation:
its right
To increase the electromagnet's strength, the student must enlarge the nail, wrap more wire around the nail, and increase the voltage of the battery. Option c is the correct answer.
How does an electromagnet work?The mechanics of an electromagnet are not overly complicated. It is accomplished by wrapping a length of conductive wire, usually copper, around a metal object.Until electricity is introduced, this appears to be nothing more than a jumbled collection of parts, similar to Frankenstein's monster. An electromagnet, on the other hand, does not require a storm to be activated. A current is introduced and flows through the wire, which can come from a battery or another source of power.As a result of the magnetic field created around the coiled wire, the metal is magnetized as if it were a permanent magnet. Electromagnets are useful because they can be activated and deactivated by closing and opening a circuit.To learn more about electromagnet, refer to
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If it takes 820 Joules of heat to warm a sample of zinc from 0°C to 50°C, what would be the mass of the zinc? Note: Zinc has a specific heat of 380 J/kg °C.
Answer:
m = 43.1 g
Explanation:
Given that,
Heat to warm the sample, Q = 820 J
Initial temperature = 0°C
Final temperature = 50°C
The specific heat of zinc is, c = 380 J/kg °C
We need to find the mass of the zinc. The specific heat in terms of mass and temperature is calculated by the relation as follows :
[tex]Q=mc\Delta T\\\\m=\dfrac{Q}{c\Delta T}\\\\=\dfrac{820}{380\times (50-0)}\\\\=0.0431\ kg\\\\=43.1\ g[/tex]
So, the mass of the sample is 43.1 g.
Answer:
43.1 g
Explanation:
Which statement correctly describes the diferences between positive and negative acceleration
O Positive acceleration describes a change in speed, negative acceleration desxibes no change in speed,
Positive acceleration describes no change in speed, negative acceleration desibes a change in speed,
Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
O Positive acceleration describes a decrease in speed, negative sideration describes an increase in sarees
Answer:The answer is this Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
Explanation:
A projectile rolls off a cliff with a velocity of 40 m/s. The cliff is 60 meters high.
1. Calculate the time the projectile takes to hit the ground
2. Calculate the distance the projectile travelled on the X-axis horizontally before hitting the ground
3. Calculate the impact velocity of the projectile on the Y-axis
4. Calculate the Resultant velocity V r
5. Calculate the angle at which the projectile hits the ground
6. Calculate Sine Θ
7. Calculate Tan Θ
8. A final Resultant Velocity Statement
Answer:
1) t = 3.45 s, 2) x = 138 m, 3) v_{y} = -33.81 m /s, 4) v = 52.37 m / s ,
5) θ = -40.2º
Explanation:
This is a projectile exercise, as they indicate that the projectile rolls down the cliff, it goes with a horizontal speed when leaving the cliff, therefore the speed is v₀ₓ = 40 m / s.
1) Let's calculate the time that Taardaen reaches the bottom, we place the reference system at the bottom of the cliff
y = y₀ + [tex]v_{oy}[/tex] t - ½ g t²
When leaving the cliff the speed is horizontal v_{oy}= 0 and at the bottom of the cliff y = 0
0 = y₀ - ½ g t2
t = √ 2y₀ / g
t = √ (2 60 / 9.8)
t = 3.45 s
2) The horizontal distance traveled
x = v₀ₓ t
x = 40 3.45
x = 138 m
3) The vertical velocity at the point of impact
v_{y} = I go - g t
v_{y} = 0 - 9.8 3.45
v_{y} = -33.81 m /s
the negative sign indicates that the speed is down
4) the resulting velocity at this point
v = √ (vₓ² + v_{y}²)
v = √ (40² + 33.8²)
v = 52.37 m / s
5) angle of impact
tan θ = v_{y} / vx
θ = tan⁻¹ v_{y} / vx
θ = tan⁻¹ (-33.81 / 40)
θ = -40.2º
6) sin (-40.2) = -0.6455
7) tan (-40.2) = -0.845
8) when the projectile falls down the cliff, the horizontal speed remains constant and the vertical speed increases, therefore the resulting speed has a direction given by the angle that is measured clockwise from the x axis
A toaster is rated at 600W, when connected to a120-V source. What current does the toaster carry, and what is its resistance?
Explanation:
Given parameters:
Power of the toaster = 600W
Voltage = 120V
Unknown:
Current = ?
Resistance = ?
Solution:
The power in the circuit is related to resistance and current using the expression below;
P = IV
P = [tex]\frac{V^{2} }{R}[/tex]
P is the power
I is the current
V is the voltage
R is the resistance
To find the current;
I = [tex]\frac{P}{V}[/tex] = [tex]\frac{600}{120}[/tex] = 5A
Now, resistance;
V² = PR
R = [tex]\frac{V^{2} }{P}[/tex] = [tex]\frac{120^{2} }{600}[/tex] = 24ohms
Current, I=5A
Resistance, R=24 ohms
Firstly, let's write the given values:
Power, P=600W
Voltage, V=120V
To find:
Current, I=?
Resistance, R=?
Lets understand ohm's Law:
Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.
Formula for Ohm's law:
[tex]V=I.R[/tex]
The relation between power, current and resistance can be represented as:[tex]P=I.V[/tex]
Or
[tex]P=\frac{V^2}{R}[/tex]
To find current:
[tex]I=\frac{P}{V}[/tex]
So on substituting given values,
[tex]I=\frac{600}{120} =5A[/tex]
To find resistance:
[tex]R=\frac{V^2}{P}[/tex]
So on substituting given values,
[tex]R=\frac{14400}{600} =24 \text{ohms}[/tex]
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angle of reflection
The angle of reflection equals the angle of Incidence
Explanation:
The Law Of Reflection
Imagine that you drop an object of 10 kg, how much will be the acceleration and
how much force causes the acceleration?
If you do this on Earth, then the acceleration of the falling object is 9.8 m/s^2 ... NO MATTER what it's mass is.
If its mass is 10 kg, then the force pulling it down is 98.1 Newtons. Most people call that the object's "weight".
Which direction of motion is affected by gravity?
Answer:
Gravity can also cause an object that is thrown into the air to change its upward motion, slow down, and fall back toward Earth's surface. The pull of Earth's gravity keeps the Moon in orbit; the moon is constantly changing direction because of gravity.
The gravitational field or gravitational potential has no direction; it's just a value that varies from place to place and over time.
Explanation:
When living things use chemical reactions to break down food, some of the energy is transformed into
OA. sound.
OB. heat.
OC. light
OD.waste
waste.
Answer:
OB. Heat
Explanation:
I hope this helped :)
Which of these is a base?
HNO3
vinegar
ammonia
HCl
The correct answer is Ammonia
Which is NOT a property of the organisms that have become useful index fossils
Answer: I dont understand
Explanation:
In an experiment, a research collected the following informationabout a solution made from a certain
food. What can we conclude about the food?
• pH = 3.0
• Taste = Sour
A. Acid
B. Base
C. Neutral
D. Salt
Answer:
salt
Explanation:
What is the mechanical advantage of a nail puller where you exert a force 45 cm from the pivot and the nail is 1.8 cm on the other side? What minimum force must you exert to apply a force of 1250 N to the nail?
Answer:
Explanation:
Mechanical Advantage is the ratio of the distance of the input load (Li)from the pivot to the output load applied to the pivot(Lo)
MA = Li/Le
Given;
Li = 45cm
Lo = 1.8cm
MA = 45/1.8
MA = 25
Hence the mechanical advantage is 25
Also MA is expressed in terms of the force ratio which is the ratio of the Load to the effort applied.
MA = Load/Effort
Given
Load = 1250N
MA = 25
Effort = ?
Substitute
25 = 1250/Effort
Effort = 1250/25
Effort = 50N
Hence the minimum force exerted on the load is 50N
When a balloon is rubbed on a surface and then touched to hair it will attract the hair, causing it to stick to the balloon. Explain why this happens.
Answer:
electricity
Explanation:
Answer:
This is called static electricity
Explanation:
The reasoning behind this is because the negative electrons in your hair are being transferred to the balloon, then when the balloon is removed it pulls on the hair with an attractive electric force.
A child sits on a merry-go-round, 1.5 meters from the center. The merry-go-round is turning at a constant rate, and the child is observed to have a radial acceleration of 2.3 m/s2. How long does it take for the merry-go-round to make one revolution
Answer:
5 .07 s .
Explanation:
The child will move on a circle of radius r
r = 1.5 m
Let the velocity of rotation = v
radial acceleration = v² / r
v² / r = 2.3
v² = 2.3 r = 2.3 x 1.5
= 3.45
v = 1.857 m /s
Time of revolution = 2π r / v
= 2 x 3.14 x 1.5 / 1.857
= 5 .07 s .
The merry-go round will take 5.07 s to complete one complete revolution.
Given data:
The distance of child from the center is, r = 1.5 m.
The magnitude of radial acceleration is, [tex]a = 2.3 \;\rm m/s^{2}[/tex].
Since, the child is on merry-go round, which is undergoing a rotational motion. And radial acceleration means that it is under the acceleration, whose value is given as,
[tex]a=\dfrac{v^{2}}{r}\\\\v=\sqrt{a \times r}[/tex]
Here, v is the linear velocity.
Solving as,
[tex]v=\sqrt{2.3 \times 1.5} \\\\v=1.857 \;\rm m/s[/tex]
Now, we to obtain the time taken by merry-go round to complete one revolution. Then the expression for the time taken to complete one revolution is,
[tex]T=\dfrac{2 \pi r}{v}\\\\T=\dfrac{2 \pi \times 1.5}{1.857}\\\\T = 5.07 \;\rm s[/tex]
Thus, we can conclude that the merry-go round will take 5.07 s to complete one revolution.
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When water changes from a gas in the atmosphere to a liquid droplet in a cloud, this is known as
Group of answer choices
transpiration
condensation
evaporation
precipitation
Answer:
Condensation
Explanation:
Answer:When water changes from a gas in the atmosphere to a liquid droplet in a cloud, this is known as
Group of answer choices
transpiration
condensation
evaporation
precipitation,←, that one is right
Explanation: so ur answer is precipitation
4). A basketball player shoots the ball in the air. It moves through the air
at 20 m/s and travels 25m. How long was the ball in the air? *
Let's start from this equation:
s = vt + s0
Know what it is? Of course you do. It's the equation used for knowing the position of an object in a certain period of time t.
s is space, v is speed, t is time, s0 is the initial space.
In this case the initial space is equal to 0 so our equation will become:
s = vt
Let's find t:
t = s/v
So:
t = 25m/20m/s = 1,25 s
---
Hope it was helpful. Have a great day!
A 300 g object attached to a horizontal spring moves in simple harmonic motion with a period of 0.340 s. The total mechanical energy of the spring–object system is 3.00 J.
(a) What is the spring constant (in N/m)?
(b) What is the amplitude (in m) of the motion?
(c) What is the percentage change in amplitude of motion if the total energy of the system is increased to 5.00 J?
Answer:
Explanation:
angular velocity ω = 2π / T where T is time period of rotation .
= 2 x 3.14 / .34 = 18.47 rad /s
Total mechanical energy = 1/2 m ω²Α² where A is amplitude .
spring constant = k
[tex]\omega=\sqrt{\frac{k}{m} }[/tex]
m is mass
[tex]\omega^2=\frac{k}{m} }[/tex]
18.47² = k / .3
k = 102.34 N /m
b )
energy = 1/2 m ω²Α²
3 = .5 x 18.47² x A²
A² = .01759
A = .1326
13.26 cm .
c )
If energy becomes 5 J
5 = .5 x 18.47² x A²
A² = .0293
A = .1711
= 17.11 cm
percent increase
= (17.11 - 13.26 )x100 / 13.26
= 29%
1. A person weighs 155 lbs and is walking 3.1 miles per hour. How much kinetic energy does the person have? (Keep in mind, 1 kg is 2.2 lb, and 1 m/s is 2.24 mi/h.)2. What is the kinetic energy of a 5 g bullet travelling 400 m/s?
3. Is it possible to have a negative KE? Why or why not?
Answer:
Explanation:
Kinetic energy is expressed as;
KE =1/2 mv²
M is the mass
v is the velocity of the object
1) Given
Mass = 155lb
Velocity = 3.1mi/hr
Since 1kg = 2.2lb
x = 155lb
x= 155/2.2
x = 70.45kg
Also
1m/s = 2.24mi/hr
y = 3.1mi/hr
y = 3.1/2.24
y = 1.384m/s
KE = 1/2(70.45)(1.384)²
KE = 0.9577×70.45
KE = 67.47Joules
2) M = 5g =0.005kg
V = 400m/s
KE = 1/2(0.005)400²
KE = 80000×0.005
KE = 400Joules
3} Since a body decelerates (negative acceleration) this mean that the velocity of a body can be a negative value showing that it is possible for a moving body to possess negative kinetic energy.
A pendulum is transported from sea-level, where the acceleration due to gravity g is 9.80 m/s2, to the bottom of Death Valley. At this location, the period of the pendulum is decreased by 3.00%. What is the value of g in Death Valley
Answer: the value of g in Death Valley is 10.417 m/s²
Explanation:
Given that;
acceleration due to gravity at the point is g = 9.8 m/s²
Lets say the acceleration due to gravity at the bottom of Death valley is g'
as the period of the pendulum is decreased by 3.00%
T' = 0.97 T
T is the period of the pendulum at sea level and T' is the period of the pendulum at bottom of Death valley
therefore from the relation
T = 2π√(l/g)
g'/g = T²/T'²
g' = (T²/ (0.97T)²)g
g' = 1.063g
g' = 10.417 m/s²
therefore the value of g in Death Valley is 10.417 m/s²
The engine of a boat (m = 2280 kg) exerts an
1800 N force northward, while the current
pushes it 1050 N eastward.
What is the magnitude of the acceleration
of the boat?
Answer:
a = 0.9139 [m/s²]
Explanation:
To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
The forces are on two different axes, x & y axes (North and East). In this way, the Pythagorean theorem should be used to determine the total force.
Fx = 1800 [N]
Fy = 1050 [N]
[tex]F = \sqrt{(F_{x} )^{2} +(F_{y} )^{2} } \\F=\sqrt{(1800)^{2} +(1050)^{2} } \\F=2083[N][/tex]
Now using Newton's second law.
ΣF = m*a
where:
F = force = 2083.8 [N] (units of Newtons)
m = mass = 2280 [Kg]
a = acceleration [m/s²]
2083.8 = 2280*a
a = 0.9139 [m/s²]
it is not uncommon for us to hold stereotypes toward people. The main advantage of forming a stereotype is that it______. The main disadvantage is that it_____.
Answer:
It is not a me mental shortcut
Explanation:
Can be changed easily
It is not uncommon for us to hold stereotypes toward people. The main advantage of forming a stereotype is that they make fast and quick decision. The main disadvantage is that they make generalized decision.
Who is a stereotype person?A stereotype is a persistent, vastly oversimplified view about a particular group or category possesses. A stereotype person make his own belief for the peoples.
A stereotype has the advantage of allowing us to respond quickly to events, since we may have had a similar experience before.
One negative is that it causes us to overlook individual distinctions, leading us to believe things about others that are not always true.
It is not uncommon for us to hold stereotypes toward people. The main advantage of forming a stereotype is that they make fast and quick decision. The main disadvantage is that they make generalized decision
The correct option for the blanks are make fast and quick decision and generalized decision.
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A 2,000 kg car travels with a tangential
velocity of 12 m/s around a circular
track with a radius of 30 meters. What
is the car's rate of centripetal
acceleration?
The car's rate of centripetal acceleration in the circular path is 4.8 m/s².
The given parameters;
mass of the car, m = 2,000 kgvelocity of the car, v = 12 m/sradius of the circular path, r = 30 mThe centripetal acceleration of the car is calculated as follows;
[tex]a_c = \frac{v^2}{r}[/tex]
where;
v is the tangential speed of the carr is the radius of the circular pathSubstitute the given parameters and solve for the centripetal acceleration;
[tex]a_c = \frac{12^2}{30} \\\\a_c = 4.8 \ m/s^2[/tex]
Thus, the car's rate of centripetal acceleration is 4.8 m/s².
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Is a compound considered a pure substance?
Answer:
It depends on which compound you use carbon dioxide can be while helium will not but if you where to sum it up it would be use because simply most compounds are considered pure substance.
Explanation:
PLZ HELP help me help help
Answer:
matter
Explanation:
Hope I helped :)
Q17: The coefficient of linear expansion of steel is a = 11 x 10-6 / °C. A steel
ball has a volume of exactly 100 cm3 at 0°C. When heated to 100°C, its
volume becomes in (cm3):
A
B
D
E
100.33
100.11
100.0011
100.0033
None of them
Solution:
The coefficient of volume expansion
p = ΔV/V1Δt
3a = V2-V1/V1Δt
Given
a = = 11 x 10-6 / °C
V2 is the final volume
V1 is the initial volume = 100cm³
Δt = 100-0 = 100°C
Substitute
3(11 x 10-6) = V2-100/100(100)
33*10^-6 * 10000 = V2-100
33*10^-2 = V2-100
V2 = 100 + 0.33
V2 = 100.33
Hence the new volume is 100.33cm³
A baseball is thrown horizontally with a velocity of 44 m/s. It travels a horizontal distance of 18
m to the plate before it is caught. How long does the ball stay in the air?
A.0.41 sec
B.41 sec
C.4.1 sec
D.4 sec
Answer:
a 0.41
plug number into equation
A horizontal baseball pitch is launched at 44 m/s. The ball will stay for 4.1 sec (approx) in the air. Hence, option C is correct.
What is Velocity?The rate at which an object's position changes when observed from a specific point of view and when measured against a specific unit of time is known as its velocity.
Its SI unit is represented as m/s, and it is a vector quantity, it means that it has both magnitude and direction.
According to the question, the given values are :
Initial Velocity, u = 44 m/s,
Distance travelled, s = 18 m and,
Final velocity, v = 0.
Use equation of motion :
v = u + at
0 = 44 + (-9.8)t
t = 44 / 9.8
t = 4.3 (approx)
Hence, the time for which the ball stay in the air is 4.1 sec (approx).
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