Answer:
2nd and 4th statements.
Explanation
If voltage is constant ( k ) and I = V / R,
Then I is inversely proportional to R so if I increases R decreases and vice versa, according to that the second statement is correct not the first.
if current is constant, then v is directly proportional to R and vice versa..the 3rd statement is wrong
if resistance is constant v is directly proportional to I, then only the 4th is correct not the 5th
V=I/R correctly expresses the relationship between voltage, current, and resistance.
True or False?
Answer:
False
Explanation:
It is actually I = V/R and V = I × R
Maria throws two stones from the top edge of a building with a speed of 20 m/s. She throws one straight down and the other straight up. The first one hits the street in a time t1. How much later is it before the second stone hits
Maria throws two stones from the top edge of a building at a speed of 20 m/s, The time is mathematically given as
t=4.5 sec.
How much later is it before the second stone hits?Generally, the equation for speed is mathematically given as
V = u+at
Therefore
0 = 22-9.8xt.
t = 22 /9.8 sec
t = 2.24489.
The same time will be taken from max^m height to point O
The extra time is taken
t=4.49 sec.
t=4.5 sec.
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a waddling armadillo of mass 500kg moves at 5 m/s. how much kinetic energy does it have?
Answer:
K=6.250 J
Explanation:
m=500kg
v=m/s
Kinetic energy= ½mv²=½(500×25) J= 6.250 J
Sian wants to measure the number of seconds that it takes for the contents of a beaker to change from clear to purple. which of these tools should she use for this purpose? an electronic balance a stopwatch a barometer a graduated cylinder
Sian wants to count the number of seconds it takes for a beaker's contents to become purple from clear. She should utilize a stopwatch as her instrument for this job.
What is a stopwatch?Watch that, when turned on and off, measures the amount of time that has passed since a specific time.
Sian wants to measure the number of seconds that it takes for the contents of a beaker to change from clear to purple. Stopwatch is the tool she should utilize for this purpose.
Hence, option B is correct.
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Answer: Sian wants to count the number of seconds it takes for a beaker's contents to become purple from clear. She should utilize a stopwatch as her instrument for this job.
option b
Explanation:
In a hard disk drive, a constant torque of 14 N⋅m is applied to the magnetic disk when the drive starts recording data. The magnetic disk has a mass of 0.2 kg and radius 2m. Determine the magnitude of the angular acceleration of the disk? [please solve if you know]
The magnitude of the angular acceleration of the magnetic disk is determined as 35 rad/s².
Angular acceleration of the disk
The angular acceleration of the disk is determined from the principle of conservation of angular momentum as follows;
τ = Iα
where;
α is angular acceleration
I is moment of inertia of the disk
I = 0.5MR²
I = 0.5 x 0.2 x 2²
I = 0.4 kgm²
τ = Iα
α = τ/I
α = (14)/(0.4)
α = 35 rad/s²
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PLease help with this this is pretty hard for me i kinda get it but not fully
Explanation:
Force = mass x acceleration
F= ma (formula)
15N = o.5kg x a
Divide both sides by o.5
a = 30 (greater acceleration)
15N = 4.5kg x a
Divide both sides by 4.5
a= 3.33 (great acceleration)
15N = 0.05kg x a
Divide both sides by 0.05
a = 300 (greatest acceleration)
A man pushes a shopping cart full of groceries at a constant velocity. What happens if the man DECREASES the force of his push on the cart?
A. The cart slows down.
B. The cart speeds up.
C. The cart moves at the same speed.
D. The cart becomes less massive.
If the man DECREASES the force of his push on the cart, the cart slows down.
Force acting on bodyThe force applied to an object is determined by applying Newton's second law of motion.
F = ma
where;
m is mass of the bodya is acceleration of the bodya = Δv/t
F = (mΔv)/t
mΔv = Ft
Δv = Ft/m
From the equation above, when the applied force decreases, the change in velocity decreases.
Thus, if the man DECREASES the force of his push on the cart, the cart slows down.
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The next closest star to Earth, Proxima Centuri, is 4.25 lightyears away. How far is that in meters?
Answer:
4.0208 x 10^16 meters
Explanation:
speed of light in m/s * # seconds in a year * 4.25 years =
2.99792 x 10^8 * 3600*24*365.25 * 4.25 = 4.0208 x 10^16 m
What is the direction of a vector that has the following components: x = -44 m y = -59 m
The direction of a vector that has the following components is 233°.
What is direction of a vector?
The direction of a vector is where its endpoint points. However, when at least one of the characteristics mentioned above is different, we say that the vectors are different.
In this case, this calculus will be:
[tex]tan\theta= \frac{59}{44} \\\theta= tan^{-1}(\frac{59}{44})\\ \theta= 233\°[/tex]
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The vector with components x = -44 m and y = -59 m has a direction of approximately 52.16 degrees counterclockwise from the positive x-axis.
The direction of a vector with components x = -44 m and y = -59 m can be determined using trigonometry. In this case, we have:
x-component (x) = -44 m
y-component (y) = -59 m
We can use the inverse tangent function to find the angle.
The direction angle (θ) can be calculated as:
θ = arctan(y / x)
θ = arctan((-59 m) / (-44 m))
Calculating this expression:
θ ≈ arctan(1.341)
To find the actual angle, we can use a calculator or table to determine the inverse tangent of 1.341.
θ ≈ 52.16 degrees
Therefore, the direction of the vector is approximately 52.16 degrees in the counterclockwise direction from the positive x-axis.
The vector with components x = -44 m and y = -59 m has a direction of approximately 52.16 degrees counterclockwise from the positive x-axis.
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-1 A 4m long wire of cross-sectional area 2.5 X 10 m² has a resistance of 5. The conductivity of the wire is (a) 2.5 X 10' m (b) 4.0 X 10' m (c) 2.5 X 10'' m¹ -1 -1 (d) 4.0 X 10''m'
Answer:
3.2 [tex]10^{-2} ohm^{-1} m^{-1}[/tex]
Explanation:
Resistance=5 ohm
Length=4m
Cross sectional area=2.5 x 10
Conductivity = 1/ resistivity
=[tex]\frac{length}{resistance x cross sectional area}[/tex]
Conductivity=4 /5 x 2.5 x 10
Conductivity=4/125
Conductivity=3.2x[tex]10^{-2}[/tex][tex]ohm^{-1} m^{-1}[/tex]
What is the net force needed to lift a full grocery sack (weighing 210 N) uniformly? What is the net force
needed to accelerate the grocery sack upward at 1.5 m/s2 ?
The net force needed to lift a full grocery sack uniformly is 32.115 N.
What is Net force?When two or more forces are acting on the system of objects, then the to attain equilibrium, net force must be zero.
Given the weight of sack W = 210N and the acceleration a = 1.5m/s².
The mass of the sack will be
m = Weight / acceleration due to gravity
m = 210 N/9.81 m/s²
m = 21.41 kg
Using Newton's second law, the net force will be
F = mass x acceleration
F= 21.41 x 1.5
F = 32.115 N
Thus, the net force is 32.115 N.
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the yacht shown below has a mass of 8300kg. determine its weight in air [ Acceleration due to gravity, g = 10 N kg¹
[tex]w = mg [/tex]
Answer:
83000kg
Explanation:
mass=8300kg
g=10
w=mg
8300×10=83000kg
a carmboard 4ft x 4ft Square has the queen at the centre the queen is hit by the striker moves to the front edge, rebounds and goes inta hole behind the striking line. find the magnitude of displacement of queen a) from the centre to front edge b) from the front end edge to hole (c) from centre to hole.
Diagonal of cardboard=displacement to hole
√4²+4²4√2So displacement till edge
4√2/22√2Total distance
4√2+2√26√2ftFrom centre to hole displacement
2√2An electromagnetic wave has a wavelength of 10 nm. Calculate its frequency and identify to which part of the electromagnetic spectrum the wave belongs.
The frequency of an electromagnetic wave with wavelength of 10nm will be 3 × 10∧7 Hz and would belong to the X-ray or ultraviolet part of the electromagnetic spectrum due to its wavelength
What is frequency?
Frequency is defined as the number of oscillations of a wave per unit time and is measured in hertz(Hz).
It is also inversely proportional to the wavelength.
How to calculate the frequency
The frequency of an electromagnetic wave can be calculated using the formula;
frequency = velocity of light divided by the wavelength
f = v ÷ λ
Note that the velocity of light = 3 × 10 ∧8 m/s
Wavelength = 10nm
Frequency, f = 3 × 10∧8 ÷ 10 = 3 × 10∧7 Hz
Hence, the frequency of an electromagnetic wave with wavelength of 10nm will be 3 × 10∧7 Hz and would belong to the X-ray or ultraviolet part of the electromagnetic spectrum due to its wavelength.
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3) A photon is emitted as the electron in a hydrogen
atom drops from the n = 5 energy level directly to
the n = 3 energy level. What is the energy of the
emitted photon?
(1) 0.85 eV
(2) 0.97 eV
(3) 1.51 eV
(4) 2.05 eV
From the information provided and the calculations, the energy of the drop is 1.51 eV
What is the Rydberg formula?The Rydberg formula is used to obtain the energy of a photon or the wavelength of a photon.
Thus;
1/λ = 1.097 * 10^7 (1/3^2 - 1/5^2)
1/λ = 1.097 * 10^7(0.11 - 0.04)
λ = 1.3 * 10^-6 m
Since;
E = hc/λ
E = 6.6 * 10^-34 * 3 * 10^8/1.3 * 10^-6
E = 1.51 * 10^-19 J or 1.51 eV
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Answer:
0.97eV
Explanation:
The energy emitted during n=5 is 0.54 eV
The energy emitted during n=3 is 1.51 eV
(This information is on the Physics Reference Table 2006 edition)
We find the change in the energy level which is:
1.51eV-0.54eV = 0.97eV
Therefore the energy emitted by the photon is 0.97eV.
A crane does exactly 1800 J of work to lift a steel beam from the ground. The beam is accidentally dropped and falls back to its starting position in 0.9 s. What is the mass of the beam
Answer:
Explanation:
1800x0.9=1620kg
Three objects have velocities that vary with time
#21
initial velocity=u=5m/sTime=t=2sAcceleration=a=1.3m/s²According to first equation of kinematics
v=u+atv=5+1.3(2)v=5+2.6v=7.6m/s#22
#a
v1=2+3(3)=2+9=11m/sv2=-8-4(3)=-20m/sv3=1-5(3)=-14m/sThe order is
v2<V3<v1#b
for speed find absolute velocity
S1=|11|=11m/sS2=|-20|=20m/sS3=|-14|=14m/sSo order is
S1<S3<S2
Answer:
See below ~
Explanation:
Question 21 :
⇒ v = u + at
⇒ v = 5 + 1.3 (2)
⇒ v = 5 + 2.6
⇒ v = 7.6 m/s
=============================================================
Question 22 : At t = 3
Subpart (a)
⇒ Object 1 : v = 2 + 3(3) = 11 m/s
⇒ Object 2 : v = -8 - 4(3) = -20 m/s
⇒ Object 3 : v = 1 - 5(3) = -14 m/s
⇒ Hence, their velocities are in the order : Object 2 < Object 3 < Object 1
Subpart (b)
⇒ Object 1 : v = | 2 + 3(3) | = 11 m/s
⇒ Object 2 : v = | -8 - 4(3) | = 20 m/s
⇒ Object 3 : v = | 1 - 5(3) | = 14 m/s
⇒ Hence, their speeds are in the order : Object 1 < Object 3 < Object 2
The centers of two 350 kg spheres are separated by 2.00 m. what is the gravitational force between them?
it is a routine composed of yells and cheers gymnastic skill and dance
Cheer dance is a routine composed of yells and cheers gymnastic skill and dance.
What is cheer dance?Cheer dance or cheerleading is a group activity used to entertain fans at athletic events and inspire louder, more enthusiastic cheering. It combines dancing and acrobatic aspects with shouted phrases.
A never-ending range of diverse stunts, jumps, pyramids, dances, and chants that integrate a variety of different movements can be included in the immensely complex sport of cheerleading. Base, partner, and spotter are the three primary cheerleading roles. These roles are all a part of cheerleading stunts, which pose the greatest risk of harm to participants.
It is a competitive sport and leisure activity made up of a set routine with necessary performance components, much like in gymnastics and dance. Additionally, it hopes to get the crowds to cheer in team sports event.
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Your question is incomplete, but most probably your full question was:
1. It is a routine composed of yells and cheers, gymnastic skills and dance.
A. Contemporary dance
B. Hip-hop dance
C. Street dance
D. Cheer dance
Gravitation always does negative work. question 48 options: true false
The statement indicating that 'Gravitation always does negative work' is FALSE.
What is Gravitation?Gravitation is a fundamental physical force that makes objects attract each other in the Universe.
This force (Gravitation) is required to maintain both constant positions and movement of objects.
In conclusion, the statement indicating that 'Gravitation always does negative work' is FALSE.
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Answer:false
Explanation:
4) An electron in a mercury atom changes from
energy level b to level e. This energy-level
change occurs as the atom.
(1) absorbs a 2.03-eV photon
(2) absorbs a 5.74-eV photon
(3) emits a 2.03-eV photon
(4) emits a 5.74-eV photon
The energy-level change occurs as the atom is absorbs a 2.03-eV photon.
Energy change of the mercury atom
The energy change of the mercury atom is calculated as follows;
Energy emitted by a photon when it falls from level b to energy level e is calculated as follows;
ΔE = -3.71 eV - (-5.74 eV)
ΔE = -3.71 eV + 5.74 eV
ΔE = 2.03 eV
When electron jumps from lower energy level to higher energy level, energy is absorbed, thus, the energy-level change occurs as the atom is absorbs a 2.03-eV photon.
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A 5000kva 230/13. 8kv single phase power transformer has a resistance of 0. 38 ohms and reactance of 1. 9 ohms
The reactance of the circuit will be 5.233×10⁻⁴ ohm. Inductive reactance is the product of 2 times π frequency and the coil inductance.
What is reactance?
When alternating electricity passes through pure reactance, it causes a voltage drop that is 90 degrees out of phase with the current.
The letter “X” is used to represent reactance in mathematics, and it is measured in ohms.
The inductive reactance of a coil is calculated using the following formula:
Inductive reactance, or XL, is the product of 2 times p (pi), and the frequency of the ac current in hertz, and the coil inductance in henries.
XL= 2πfL
Where,
f {frequency)
L (Inductance)
The reactance of the circuit is found as;
[tex]\rm R_{new}=0.38[{(\frac{1}{60} )^2][/tex]
[tex]\rm R_{new}=1.055 \times 10^{-4} \ ohm[/tex]
The inductance of the circuit is;
[tex]\rm X_{new}=1.9(\frac{1}{60} )^2\\\\X_{new}= 5.233 \times 10^{-4}\ ohm[/tex]
Hence, the reactance of the circuit will be 5.233×10⁻⁴ ohm.
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Estimate how long a 2500 W electric kettle would take to boil away 1.5 Kg of water . The specific latent heat of vaporization of water is 4000000 J / Kg .
The time it would take a 2500 W electric kettle to boil away 1.5 Kg of water is 2400 seconds
How to calculate the timeUse the formula:
Power × time = mass × specific heat
Given mass = 1. 5kg
Specific latent heat of vaporization = 4000000 J/ Kg
Power = 2500 W
Substitute the values into the formula
Power × time = mass × specific heat
2500 × time = 1. 5 × 4000000
Make 'time' the subject
time = 1. 5 × 4000000 ÷ 2500 = 6000000 ÷ 2500 = 2400 seconds
Therefore, the time it would take a 2500 W electric kettle to boil away 1.5 Kg of water is 2400 seconds.
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Cool air tends to...
A. Be less dense and flow over warm air.
B. Be lifted up by more dense warm air.
C. Be more dense and flow under warm air.
D. Mix easily with warm air masses.
Answer: C. Be more dense and flow under warm air.
Explanation:
think of a supermarket selling dairy products and when you open the fridge to get the milk, outside the supermarket is hot and inside the fridge is cold ice.
Parallel light rays are refracted _______and_____ to a point called as focal point after passing through convex lens.
Open the attached file. It shows 2 waves (a blue one and an orange one) that are moving through the same medium at the same time. Your challenge is to DRAW the RESULTANT wave and LABEL the areas of interference with CI, DI and/or points of TDI.
The diagram is labelled to DRAW the RESULTANT wave and LABEL the areas of interference with CI, DI and/or points of TDI.
What is refraction?When a light ray falls on the interface of two medium like air and water, then the portion of light is reflected and another portion of the light is refracted into the water medium. The angle of incidence is equal to the angle of reflection but the angle of incidence is larger then the angle of refraction.
Open the attached file. It shows 2 waves (a blue one and an orange one) that are moving through the same medium at the same time.
Thus, the diagram is labelled.
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Which quantity is a vector quantity?
A.
displacement
B.
distance
C.
mass
D.
temperature
E.
volume
Answer:
Displacement...
Explanation:
Displacement is a vector quantity as it have both magnitude and direction...
[tex]...[/tex]
a. displacement is the correct answer
Displacement is a vector quantity
EXPLANATIONDisplacement is a vector quantity because it has both magnitude and direction.
The mass of a bicyclist and a bicycle together is 53.0 kg. How much work has been
done if the bicyclist slows the bicycle from a speed of 3.84 m/s to 1.27 m/s?
(A) -68.1 J
(B) -136 J
(C) -348 J
(D) -696 J
Answer:
Approximately [tex](-348\; {\rm J})[/tex], assuming that the bike was on level ground.
Explanation:
If an object of mass [tex]m[/tex] is moving at a speed of [tex]v[/tex], the kinetic energy of that object would be [tex](1/2)\, m\, v^{2}[/tex].
At a speed of [tex]v = 3.84\; {\rm m\cdot s^{-1}}[/tex], the kinetic energy of the bike and the cyclist- combined- would be:
[tex]\begin{aligned} &\frac{1}{2}\, m\, v^{2} \\=\; &\frac{1}{2}\times 53.0\; {\rm kg} \times (3.84\; {\rm m\cdot s^{-2}})^{2} \\ \approx \; & 390.76\; {\rm J}\end{aligned}[/tex].
At a speed of [tex]v = 1.27\; {\rm m\cdot s^{-1}}[/tex], the kinetic energy of the bike and the cyclist- combined- would be:
[tex]\begin{aligned} &\frac{1}{2}\, m\, v^{2} \\=\; &\frac{1}{2}\times 53.0\; {\rm kg} \times (1.27\; {\rm m\cdot s^{-2}})^{2} \\ \approx \; &42.741 \; {\rm J}\end{aligned}[/tex].
The energy change was approximately:
[tex]390.76\; {\rm J} - 42.741\; {\rm J} \approx 348\; {\rm J}[/tex].
If the bike was on level ground, the friction on the bike and the cyclist would have done a work of [tex](-348\: {\rm J})[/tex] to reduce the kinetic energy of the bike and the cyclist by that amount.
Answer: C) -348J
Explanation:
42.741 - 390.76 (the kinetic energy of the two speeds) is equal to -348.
Sheila weighs 60 kg and is riding a bike. Her momentum on the bike is 340 kg • m/s. The bike hits a rock, which stops it completely and throws Sheila forward onto the pavement.
If there is no net force on the system, what is Sheila’s velocity immediately after she is thrown from the bike?
1.8 m/s
2.0 m/s
5.0 m/s
5.7 m/s
From the calculation, Sheila’s velocity immediately after she is thrown from the bike is 5.7 m/s.
What is momentum?Momentum is the product of mass and velocity. We know that the momentum before collision is equal to the momentum after collision.
Hence;
Momentum before collision = 340 kg • m/s.
Momentum after collision = 60v
Thus;
340 kg • m/s = 60v kg • m/s
v = 340 kg • m/s/60 Kg
v = 5.7 m/s
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a tape is weighed and found to weigh 1.95 lb. the overall length of the 100-ft tape (end to end) is 102.00 ft. the specific weight of steel is 490 lb/ft?. what is the cross-sectional area of the tape?
The cross-sectional area of the tape is determined as 3.9 x 10⁻⁵ ft².
Volume of the tape
The volume of the tape is calculated as follows;
volume = mass/density
volume = (1.95 lb)/(490 lb/ft³)
volume = 3.98 x 10⁻³ ft³
Area of the tapeV = AL
A = V/L
A = 3.98 x 10⁻³ ft³/102 ft
A = 3.9 x 10⁻⁵ ft²
Thus, the cross-sectional area of the tape is determined as 3.9 x 10⁻⁵ ft².
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