Answer:
Q = 282,000 J
Explanation:
Given that,
The mass of liquid water, m = 125 g
Temperature, T = 100°C
The latent heat of vaporization, Hv = 2258 J/g.
We need to find the amount of heat needed to vaporize 125 g of liquid water. We can find it as follows :
[tex]Q=mH_v\\\\Q=125\ g\times 2285\ J/g\\\\Q=282250\ J[/tex]
or
Q = 282,000 J
So, the required heat is 282,000 J .
A police officer uses a radar gun that emits electromagnetic waves with a frequency of 10.525 GHz (1.0525 1010 Hz). Assume the police officer is at rest, and is aiming the radar gun at vehicles traveling either directly toward, or directly away from, the radar gun. Assume the speed limit is 110 km/h, as it is on many Canadian highways. The police officer observes reflected waves that have a frequency of 2460 Hz below the frequency of the emitted waves.
Required:
a. At what speed is the car moving?
b. Choose the two correct statements about this situation.
1. The car is moving toward the police officer.
2. The car is moving away from the police officer.
3. The police officer should not cite the driver for speeding.
4. The police officer should cite the driver for speeding.
Answer:
Explanation:
For Doppler effect in radar the formula is as follows
Δf = f₀ x 2v /c
Δf is change in frequency in reflected wave , f₀ is original frequency , v is velocity of source and c is velocity of right .
Δf = 2460 Hz , f₀ = 1.0525 x 10¹⁰ Hz , v = ? c is velocity of light .
2460 = 1.0525 x 10¹⁰ x 2 v / 3 x 10⁸
2460 = 105.25 x 2 v / 3
v = 2460 x 3 / (105.25 x 2 )
v = 35 .06 m /s .
(b)
Since the observed frequency is less , the source is moving away from the observer .
option (2) is correct .
Why are special techniques and extinguishing agents are required to fight combustible metals fires?
As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. When you push the platform, you compress the springs. You do an amount of work of 76.0 J when you compress the springs a distance of 0.170 m from their uncompressed length.
(a) What magnitude of force must you apply to hold the platform in this position?
(b) How much additional work must you do to move the platform 0.200 m farther, and what maximum force must you apply?
Answer:
[tex]894.12\ \text{N}[/tex]
[tex]284.013\ \text{J}[/tex]
Explanation:
U = Energy = 76 J
x = Displacement of spring = 0.17 m
k = Spring constant
Energy is given by
[tex]U=\dfrac{1}{2}kx^2\\\Rightarrow k=\dfrac{2U}{x^2}\\\Rightarrow k=\dfrac{2\times 76}{0.17^2}\\\Rightarrow k=5259.51\ \text{Nm}[/tex]
Force is given by
[tex]F=kx\\\Rightarrow F=5259.51\times 0.17\\\Rightarrow F=894.12\ \text{N}[/tex]
The magnitude of force must you apply to hold the platform is [tex]894.12\ \text{N}[/tex].
Now [tex]x=0.17+0.2=0.37\ \text{m}[/tex]
[tex]U=\dfrac{1}{2}kx^2\\\Rightarrow U=\dfrac{1}{2}\times 5259.51\times 0.37^2\\\Rightarrow U=360.013\ \text{J}[/tex]
Additional energy
[tex]360.013-76=284.013\ \text{J}[/tex]
Need a little help here, ASAP please. The subject is simple science, not physics.
What is relative density?
how much force is needed to accelerate a 2500kg car at a rate of 4m/s2
Answer:
10,000 N
Explanation:
Using Newton's Second Law of Motion, Force = Mass*Acceleration.
Plugin 2500 kg for the mass and 4 m/s^2 for the acceleration.
Force = 2500 kg*4 m/s^2 = 10000 Newtons
(SI unit of force is Newtons)
Help please thank you
anser: 27s PoP
Explanation:
1 is the force, so the equal antiforce will be 1. weight of car divided by force from engine
34 pop / s = 129
27pOp
A 55.0 kg bungee jumper steps off a bridge with a light bungee cord tied to her and to the bridge. The unstretched length of the cord is 15.0 m. She reaches the bottom of her motion 40.0 m below the bridge before bouncing back. Her motion can be separated into an 15.0 m free-fall and a 25.0 m section of simple harmonic oscillation. Use the principle of conservation of energy to find the spring constant of the bungee cord.
Answer:
[tex]69.06\ \text{N/m}[/tex]
Explanation:
m = Mass of bungee jumper = 55 kg
g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]
h = Height at the bottom = 40 m
k = Spring constant
x = Displacement of bungee cord = 25 m
Applying the principle of conservation of energy to the system we have
[tex]mgh=\dfrac{1}{2}kx^2\\\Rightarrow k=\dfrac{2mgh}{x^2}\\\Rightarrow k=\dfrac{2\times 55\times 9.81\times 40}{25^2}\\\Rightarrow k=69.06\ \text{N/m}[/tex]
The spring constant of the bungee cord is [tex]69.06\ \text{N/m}[/tex].
how are characteristics of electromagnetic waves affected by medium
Hello,
QUESTION)Light is an electromagnetic wave, its speed is maximum in space and almost in the air where interactions have almost no effect. In other non-opaque media, light is subject to several phenomena: refraction and reflection. Part of the incident ray will be reflected in the same medium while the other part will be refracted in the new medium with a lower speed. In general, the medium influences the speed, and therefore the wavelength.
What must exist for the engineering process to begin?
a. a problem
ь.a solution
c. research
d. scientific tools
Answer:
d
Explanation:
rzp-yyib-oiv
plèase jóin ón góógle mèèt
Answer:
a. a problem
Explanation:
The engineering process begins by defining a problem and completing background research on the problem.
What is Gravity?
PLEASE ANSWER
Answer:
Gravity is the force by which a planet or other body draws objects toward its center. The force of gravity keeps all of the planets in orbit around the sun.
Please mark as brainliest
Have a great day, be safe and healthy
Thank u
XD
Answer:
GRAVITY:
In physics, gravity is the force that attracts a body towards the centre of the earth, or towards any other physical body having mass.
After landing on an unexplored Klingon planet, Spock tests for the direction of the magnetic field by firing a beam of electrons in various directions and by recording the following observations:1. Electrons moving upward feel a magnetic force in the northwest direction.2. Electrons moving horizontally toward the north are pushed downward.3. Electrons moving horizontally toward the southeast are pushed upward.Mr. Spock therefore concludes that the magnetic field at this landing site is in which direction?A) toward the eastB) toward the northeastC) toward the southwestD) toward the southeastE) toward the west
Answer:
the correct one is C,
Explanation:
The magnetic force is given by the expression
F = q v x B
where the bold letters indicate vectors, we can find the modulus of this expression
F = q v B sin θ
The direction of the to the force with the rule of the right hand. The thumb applies in the direction of the speed, the fingers extended in the direction of the magnetic field and if the charge is positive the palm is in the direction of the force, if the charge is megative the force is in the opposite direction to the palm of hand.
Let's analyze the different situations presented; As the particles emitted are electrons, their charge is negative.
Situation 1. The thumb points upwards, the force is towards the NW as the charge is negative, the palm points towards the SE therefore the finger points towards the SOUTHWEST which must be the direction of the magnetic field
Situation 2. the electrons go horizontally to the north the thumb points in this direction, the force is downwards, therefore the palm points upwards, the extended fingers point to the WEST
Situation 3. the thumb points to the SE towards where the electrons move, the force is upwards the palm points to the SW, therefore the fingers extended points SOUTHWEST
As a result of situations 1 and 3 the magnetic field must point in the SOUTHWEST direction.
Situation 2 gives a different result because the component of the field that is directed to the south does not create exerts and therefore cannot be detected.
When checking the answers, the correct one is C
a car whose tires have radii of 50cm travels at 20km/h. what is the angular velocity of the tire
Answer:
0.225 s^-1
Explanation:
Please mark as brainliest
The angular velocity of the tire is 11.12 rad/s.
Angular velocity: This is the change in angular direction per time. The S.I unit is rad/s.
⇒ Formula:
v = rω.................... Equation 1⇒ Where:
v = linear velocity of the carr = radius of the carω = angular velocity of the car⇒ Make ω the subject of the equation
ω = v/r.............. Equation 2From the question,
⇒ Given:
v = 20 km/h = 20(1000)/(3600) m/s = 5.56 m/sr = 50 cm = 50/100 = 0.5 m⇒ Substitute these values into equation 2
ω = 5.56/0.5ω = 11.12 rad/sHence, The angular velocity of the tire is 11.12 rad/s
Learn more about angular velocity here: https://brainly.com/question/20432894
faraday's law states that the potential difference can be increased by... (choose all that apply)
1. using static electricity instead of current electricity
2. increase the number of coils, increase the strength of the magnet
3. using a bunch of small magnets
4. increasing the time used to power up an electromagnet
5. increase the speed of the magnet
Id say its the last option of the fourth option
Explanation:
Answer:
1:increase the number of coils, increase the strength of the magnet
2:increase the speed of the magnet
3: increasing the time used to power up an electromagnet
Explanation:
1). Increasing the number of turns of wire in the coil – By increasing the amount of individual conductors cutting through the magnetic field, the amount of induced emf produced will be the sum of all the individual loops of the coil, so if there are 20 turns in the coil there will be 20 times more induced emf than in one piece of wire.
2). Increasing the speed of the relative motion between the coil and the magnet – If the same coil of wire passed through the same magnetic field but its speed or velocity is increased, the wire will cut the lines of flux at a faster rate so more induced emf would be produced.
3). Increasing the strength of the magnetic field – If the same coil of wire is moved at the same speed through a stronger magnetic field, there will be more emf produced because there are more lines of force to cut.
what is the formula that describes the magnitude of impulse on an object?
Answer:
Option C.
Impulse = mass × change in velocity
Explanation:
Impulse is defined by the following the following formula:
Impulse = force (F) × time (t)
Impulse = Ft
From Newton's second law of motion,
Force = change in momentum /time
Cross multiply
Force × time = change in momentum
Recall:
Impulse = Force × time
Thus,
Impulse = change in momentum
Recall:
Momentum = mass x velocity
Momentum = mv
Chang in momentum = mass × change in velocity
Change in momentum = mΔv
Thus,
Impulse = change in momentum
Impulse = mass × change in velocity
. Four railroad cars, each of mass 2.50 104 kg, are coupled together and coasting along horizontal tracks at a speed of vi toward the south. A very strong but foolish movie actor, riding on the second car, uncouples the front car and gives it a big push, increasing its speed to 4.00 m/s southward. The remaining three cars continue moving toward the south, now at 2.00 m/s. (a) Find the initial speed of the cars. (b) How much work did the actor do
Answer:
a) v₀ = 2.5 m / s, heading south.
b) W = 1,219 10⁵ J
Explanation:
a) For this exercise we can use the conservation of the moment, we create a system formed by all the 4 cars, in this case when the last one separates the forces are intense and the moment is conserved
initial instant. Before separation
p₀ = M v₀
final instant. When uncoupling the last car
p_f = 3m v₁ + m v₂
where they indicate that the speed of the wagons is v₁ = 2.00 m / s and the speed of the last wagon is v₂ = 4.00 m / s
the total mass is M = 4m
how the moment is preserved
p₀ = p_f
4m v₀ = 3m v₁ + mv₂
v₀ = ¾ v₁ + v₂ / 4
let's calculate
v₀ = ¾ 2 + ¼ 4
v₀ = 2.5 m / s
heading south.
b) work is equal to the change in kinetic energy
W = ΔK = K_f -K_o
W = ½ m v_f² - ½ m v₀²
W = ½ m (v_f² -v₀²)
W = ½ 2.50 10⁴ (4² - 2.5²2)
W = 1,219 10⁵ J
The work-energy theorem states that a force acting on a particle as it moves over a ______ changes the ______ energy of the particle if the force has a component parallel to the motion. Choose the best answer to fill in the blanks above: Choose the best answer to fill in the blanks above: distance / potential distance / kinetic vertical displacement / potential none of the above
Answer: The work-energy theorem states that a force acting on a particle as it moves over a DISTANCE changes the KINETIC energy of the particle if the force has a component parallel to the motion.
Explanation:
The work- energy theorem states that the work done when forces act on particles as it moves over a distance is equal to the change in Kinetic energy of the particle if the force has a component parallel to the motion. To express this definition an equation is used:
W= ∆K.E =(final K. E. - initial K. E)
Therefore W= ½mv²(final) - ½mv²(initial)
Where W is work done by net force and
K.E ( final minus the initial) is the particle change in Kinetic Energy.
According to this theorem, when an object slows down, its final kinetic energy is less than its initial kinetic energy, the change in its kinetic energy is negative, and so is the net work done on it. If an object speeds up, the net work done on it is positive. When calculating the net work, you must include all the forces that act on an object.
This theorem also shows that since work done on a particle can lead to change in its kinetic energy, it implies that work can transfer energy from one form to another.
Answer:
The work-energy theorem states that a force acting on a particle as it moves over a distance changes the kinetic energy of the particle if the force has a component parallel to the motion.
Explanation:
The correct answer is presented below and all reasons are presented to explain all facts:
The work-energy theorem states that a force acting on a particle as it moves over a distance changes the kinetic energy of the particle if the force has a component parallel to the motion.
Reasons:
According to the Work-Energy Theorem, the work done on a particle ([tex]W[/tex]) equals the change in its kinetic energy ([tex]\Delta K[/tex]). That is:
[tex]W = \Delta K[/tex] (1)
By definition of work we expand this definition:
[tex]\oint \vec F\,\bullet\,d\vec s = \Delta K[/tex] (2)
Where:
[tex]\vec F[/tex] - Vector force.
[tex]\vec s[/tex] - Vector travelled distance.
And by definition of dot product we conclude that:
[tex]\int\limits_{A}^{B}{\|\vec F\|\cdot \|d\vec{s}\|\cdot \cos \phi} = \Delta K[/tex]
Where:
[tex]\|\vec F\|[/tex] - Magnitude of the vector force.
[tex]\|d\vec s\|[/tex] - Magnitude of the differential of the vector travelled distance.
[tex]\phi[/tex] - Angle between vectors, measured in sexagesimal degrees.
[tex]A, B[/tex] - Initial and final position of the particle.
From this expression we infer that change in kinetic energy is maximum if and only if [tex]\phi = 0^{\circ}[/tex] in every point of the path travelled by the particle. In addition, change in kinetic energy occurs when component of force parallel to path is not zero.
I need help with science please, ill give brianlist’s :
Question 1 :The size of a plant cell may change depending upon the amount of water it receives.
True
False
________________________________
Question 2: Chloroplasts are a category of organelles found in the cells of green plants.
True
False
_______________________________
Question 3: Photosynthesis in plants produces water and carbon dioxide.
True
False
Answer:
true , true, and I'm not sure about the last one!
Explanation:
11. There are 2 main reasons geologists think the continents were once connected. One
reason is that some coastlines share similar fossils. What is the other reason? II
Answer:
they all kinda fit together like a puzzle also because they can tell now that the continates are moving so, they can asume that they have always been moving
In fatal crashes, more than __________% of passenger car occupants who were totally ejected from the vehicle were killed.
Answer:
it would be 83% in a fatal crash.
A student adds 5 grams of vinegar to 7 grams of baking soda in a sealed bag. Then she watches the bag inflate as a chemical
reaction occurs. Which of these amounts is a CORRECT prediction of the mass of the materials in the container after the reaction is
complete?
Answer:
The mass will stay the same if the bag stays sealed.
Explanation:
PLEASE HELP ME WITH THIS ONE QUESTION
1000 J of energy is given to a balloon via a heating device. Assuming the pressure is a constant 101,325 Pa, what is the final volume of the balloon, assuming it started at 0.001 m3?
Answer:
Vf = 0.0108 m³
Explanation:
Assuming there is no change in internal energy, we can calculate the changed volume by the following formula:
[tex]Energy\ Supplied = Work = W = P \Delta V \\W = P(V_{f}-V_{i})\\[/tex]
where,
W = Work = Energy Supplied = 1000 J
P = Pressure = 101325 Pa
Vf = Final Volume = ?
Vi = Initial Volume = 0.001 m³
Therefore,
[tex]1000\ J = (101325\ Pa)(V_{f}-0.001\ m^3)\\\\V_{f}-0.001\ m^3 = \frac{1000\ J}{101325\ Pa}\\\\V_{f} = 0.001\ m^3 + 0.0099\ m^3[/tex]
Vf = 0.0108 m³
The diagram illustrates the movement of sound waves between an observer and a race car. As the race car drives away from the observer, notes that the sound from the car gets quieter and the pitch lowers. Which statement is the MOST plausible question the observer might ask to explain the
phenomenon she experiences?
A. Why does the sound of the engine change as the car drives away?
B. What is the effect of the change in speed of the car and the pitch of the sound?
C. What is the relationship between the volume of the sound and the pitch of the sound
of the car?
D. How do changes in frequency and amplitude affect the pitch of the sound generated
by the car?
A Cambra pouce car traveling at 28 m/s slow
at a rate of at 3.6 m/s every second find.
a) The time taken for the police car to come to Stop?
Answer:
t = 7.8 seconds
Explanation:
Given that,
The initial speed of the car, u = 28 m/s
Acceleration of the car, a = 3.6 m/s²
We need to find the time taken for the police car to come to Stop. When it stops, its final speed is equal to 0. So, using the equation of kinematics to find it i.e.
[tex]v=u+at\\\\0=28+3.6t\\\\t=\dfrac{28}{3.6}\\\\t=7.8\ s[/tex]
So, the required time is 7.8 seconds.
Find the velocity of a dolphin that swims 55 m in 5.0 s.
Answer: 11 m/s
Explanation: velocity = distance /time = 55 m /5.0 s
Answer:40km/h
Explanation:
The collision of objects which generates thermal energy is called _______________________________
A
Conduction
B
Force
C
Power
D
Newton
Answer:
a. Conduction
Explanation:
A 1.5 V battery produces 41.8 mA when it is across a 30.0 Ω load. The potential difference across the battery's terminals is
Answer:
Explanation:
V = I R
V = 0.0418 * 30
V = 1.254
this battery seems dead :P
Answer:
Explanation:
Let's just assume that the battery has no internal resistance. If we get an absurd answer, we'll come back and look at that assumption.
E = I * R
I = 41.8/1000 amps = 0.0418
R = 30.0 ohms
E = 0.0418 * 30
E = 1.254 volts. This is an OK answer. The battery is a little old.
which of the following characteristics is most useful for flower identification
Answer:
basically needing sunlight and water
Explanation:
hope it helps
Which of these is NOT a form of energy?
A. mechanical
B. chemical
C. theoretical
D. thermal
Answer:
I think it's theoretical.
Two resistors R1 = 3 Ω and R2 = 6 Ω are connected in parallel. What is the net resistance in the circuit?
Answer:
"2Ω" is the net resistance in the circuit.
Explanation:
The given resistors are:
R1 = 3Ω
R2 = 6Ω
The net resistance will be:
⇒ [tex]\frac{1}{R_{net}} =\frac{1}{R_1} +\frac{1}{R_2}[/tex]
On substituting the values, we get
⇒ [tex]\frac{1}{R_{net}} =\frac{1}{3} +\frac{1}{6}[/tex]
On taking L.C.M, we get
⇒ [tex]\frac{1}{R_{net}} =\frac{2+1}{6}[/tex]
⇒ [tex]\frac{1}{R_{net}} =\frac{3}{6}[/tex]
⇒ [tex]\frac{1}{R_{net}} =\frac{1}{2}[/tex]
On applying cross-multiplication, we get
⇒ [tex]R_{net}=2 \Omega[/tex]
