Answer:
Explanation:18kt alloy contains
i) 75% of gold
rhogold=19.3g/cm^3
=75/100×19.3
=14.475g/cm^3
ii) 16% of silver
rhosilver=10.5g/cm^3
=16/100×10.5
=1.68g/cm^3
iii) 9% of copper
rhocopper =8.90g/cm^3
=9/100×8.9
=0.801g/cm^3
Overall density of 18kt gold
=(0.801+1.68+14.475)g/cm^3
=16.956g/cm^3
=17g/cm^3 to 3s.f
descibe a transferwave
Answer: I think you meant transverse wave. A transverse wave is a moving wave whose oscillations are perpendicular to the direction of the wave or path of propagation. A simple example is given by the waves that can be created on a horizontal length of string by anchoring one end and moving the other end up and down.
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A proton starts from rest, and moves 1 meter through a constant electric field. The potential difference between its starting and ending points is 500 V. How fast is the proton moving at the end? How large is the electric field? How long does it take the proton to complete its journey? [Late clarification: since the field is accelerating the particle from rest, you can assume that the direction of the particle's motion is parallel to the field.]
Answer:
E = - 500 V / m, v = 30.95 10⁴ m / s and t = 6.46 10⁻⁶ s
Explanation:
For this problem we use the relation
ΔU = - E s
E = -ΔU / s
E = - 500/1
E = - 500 V / m
Now we can look for the proton approach
F = q E
let's use Newton's second law
F = m a
a = F / m
a = q E / m
Now let's use kinematics relations, where the proton starts from the rest
v₀ = 0
v² = v₀² + 2 a x
v = √2 q E / m x
v = √ (2 1.6 10⁻¹⁹ 500 / 1.67 10⁻²⁷ 1)
v = √ (958.08 108)
v = 30.95 10⁴ m / s
for time let's use the equation
x = v₀ t + ½ to t2
t = √2x / a
t = √ (2x m / qE)
t = √ (2 1 1.67 10⁻²⁷ / (1.6 10⁻¹⁹ 500))
t = √ (0.004175 10⁻⁸)
t = 0.0646 10⁻⁴ s
t = 6.46 10⁻⁶ s
A Ferris wheel has a 40-foot radius and the center of the Ferris wheel is 48 feet above the ground. The Ferris wheel rotates in the CCW direction at a constant angular speed of 2 radians per minute. Enrique boards the Ferris wheel at the 3-o'clock position and rides the Ferris wheel for many rotations. Let t represent the number of minutes since the ride started.
Write an expression (in terms of t ) to represent the number of radians Enrique has swept out from the 3-o'clock position since the ride started.
Answer:
[tex]\theta=\frac{\pi}{4}+2\frac{rad}{s}t[/tex]
Explanation:
To find the expression in terms of time t you take into account the following equation for the angular distance traveled by an object with angular acceleration w and initial angular position θo:
[tex]\theta=\theta_o+\omega t+\frac{1}{2}\alpha t^2[/tex] ( 1 )
α is the angular acceleration, but in this case you have a circular motion with constant angular speed, then α = 0 rad/s^2. θo is the initial angular position, the information of the question establishes that Enrique is at 3-o'clock. This position can be taken, in radian, as π/4 (for 12-o'clock = 0 rads).
The angular speed is:
[tex]\omega=2\frac{rad}{min}[/tex]
You replace the values of θo, α and w in the equation ( 1 ):
[tex]\theta=\frac{\pi}{4}+2\frac{rad}{s}t[/tex]
Furthermore, the arc length is:
[tex]s=r\theta=(40ft)[\frac{\pi}{4}+2\frac{rad}{s}t][/tex]
A mass weighting 48 lbs stretches a spring 6 inches. The mass is in a medium that exerts a viscous resistance of 27 lbs when the mass has a velocity of 6 ft/sec. Suppose the object is displaced an additional 6 inches and released.
Required:
a. Find an equation for the object's displacement, u(t), in feet after t seconds.
b. What is the mass of the object?
c. What is the damping coefficient?
d. What is the spring constant?
Answer:
a)
[tex]u(t)=0.499ft.e^{-\frac{144.76lb/s}{2(48lb)}t}cos(\omega t)\\\\u(t)=0.499ft.e^{-1.5t}cos(\omega t)[/tex]
b)
m = 48lb
c)
b = 144.76lb
Explanation:
The general equation of a damping oscillate motion is given by:
[tex]u(t)=u_oe^{-\frac{b}{2m}t}cos(\omega t-\alpha)[/tex] (1)
uo: initial position
m: mass of the block
b: damping coefficient
w: angular frequency
α: initial phase
a. With the information given in the statement you replace the values of the parameters in (1). But first, you calculate the constant b by using the information about the viscous resistance force:
[tex]|F_{vis}|=bv\\\\b=\frac{|F_{vis}|}{v}\\\\|F_{vis}|=27lbs=27*32.17ft.lb/s^2=868.59ft.lb/s^2\\\\b=\frac{868.59}{6}lb/s=144.76lb/s[/tex]
Then, you obtain by replacing in (1):
6in = 0.499 ft
[tex]u(t)=0.499ft.e^{-\frac{144.76lb/s}{2(48lb)}t}cos(\omega t)\\\\u(t)=0.499ft.e^{-1.5t}cos(\omega t)[/tex]
b.
mass, m = 48lb
c.
b = 144.76 lb/s
A living thing that has a irregular shape is
Answer:
Amoeba
Explanation:
You may say that the shape appears irregular. Infact, Amoeba has no definite shape, unlike other organisms. It keeps on changing its shape.
what bo you nmean by ABC rule ?
A large truck and a small car are moving at the same speed. The truck has a greater kinetic energy because its _________ is greater
Answer:
The answer is mass .
Explanation:
The kinetic energy formula is :
[tex]k.e = \frac{1}{2} m {v}^{2} [/tex]
So if the mass is higher, the kinetic energy gained is higher .
If a large truck and a small car are moving at the same speed. The truck has greater kinetic energy because its mass is greater, as the kinetic energy of a body depends on the mass as well as the speed of the object.
What is mechanical energy?Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total stored energy in the system which is represented by total potential energy.
The kinetic energy of the Truck is given by the expression,
K.E= 1/2*m*v²
Where K.E is the kinetic energy of the object
m is the mass of the truck
v is the velocity of the truck
Since the speed is the same for both cars and the truck has greater kinetic energy because its mass is greater.
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In a certain electronic device, charged particles must make their way through a magnetic field without experiencing any forces. This can be accomplished if
O A. B is perpendicular to v
B. their charges are negative
O c. they move parallel to the magnetic field
OD. the angle between the charges' velocity and the magnetic field is 90°
Answer:
Se mas clara
Explanation:
According to recent typical test data, a Ford Focus travels 0.240 mi in 19.3 s, starting from rest. The same car, when braking from 62.5 mph on dry pavement, stops in 150 ft. Assume constant acceleration in each part of its motion, but not necessarily the same acceleration when slowing down as when speeding up.(a) Find the magnitude of this car's acceleration while braking.(b) Find the magnitude of this car's acceleration while speeding up.(c) If its acceleration is constant while speeding up, how fast (in mph) will the car be traveling after 0.250 mi of acceleration?(d) How long does it take the car to stop while braking from 59.0 mph?
Answer:
Explanation:
a )
While breaking initial velocity u = 62.5 mph
= 62.5 x 1760 x 3 / (60 x 60 ) ft /s
= 91.66 ft / s
distance trvelled s = 150 ft
v² = u² - 2as
0 = 91.66² - 2 a x 150
a = - 28 ft / s²
b ) While accelerating initial velocity u = 0
distance travelled s = .24 mi
time = 19.3 s
s = ut + 1/2 at²
s is distance travelled in time t with acceleration a ,
.24 = 0 + 1/2 a x 19.3²
a = .001288 mi/s²
= 2.06 m /s²
c )
If distance travelled s = .25 mi
final velocity v = ? a = .001288 mi / s²
v² = u² + 2as
= 0 + 2 x .001288 x .25
= .000644
v = .025 mi / s
= .0025 x 60 x 60 mi / h
= 91.35 mph .
d ) initial velocity u = 59 mph
= 86.53 ft / s
final velocity = 0
acceleration = - 28 ft /s²
v = u - at
0 = 86.53 - 28 t
t = 3 sec approx .
An insulating plastic rod is charged by rubbing it with a wool cloth, and then brought to an initially neutral conducting metallic sphere sitting on an insulating stand. The rod touches the sphere for a few seconds, and then is separated from the sphere by a small distance. After the rod is separated, the rod:_____
A) is repelled by the sphere.
B) is attracted to the sphere.
C) feels no force due to the sphere.
Answer:
A) is repelled by the sphere.
Explanation:
When a charged insulated rod is touched with an insulated conducting sphere , some charge on the rod gets transferred to the sphere . So they become similarly charged . We all know that there is repulsion when two similarly charged object are brought near to each other . Hence here too there will be repulsion between the rod and the sphere when the rod is brought near the sphere.
In this example we will see how a transformer can be used to change the voltage output of a wall receptacle. A friend returns from Europe with a device that she claims to be the world's greatest coffee maker. Unfortunately, it was designed to operate from a 240 V line, standard in Europe. At this rms voltage, the coffee draws 1500 W of power. (a) If your friend wants to operate the coffee maker in the United States, where the rms line voltage is 120 V, what turns ratio does her transformer need to have for the coffee maker to work
Answer:
Explanation:
In order to use a device rated for use in 240 volt for use in 120 V , we have to use a step down transformer . In step down transformer no of turn in secondary coil is less than that in primary coil .
For transformer the relation is as follows
V₂ / V₁ = N₂ / N₁ = turn ratio
Where V₂ and V₁ are volts in secondary and primary coil and N₂ and N₁ is no of turns in secondary and primary coil.
Here V₂ = 120V , V₁ = 240 V
turn ratio = N₂ / N₁ = V₂ / V₁ = 120 / 240 = .5
turn ratio = .5 .
A rigid uniform rod of length 90.0 cm and mass 35.0 kg laying on a horizontal frictionless surface is free to rotate on that surface about an axle through its center. A small puck slides into it at an angle of 90 degrees to its surface at a distance of 30.0 cm from the pivot point at a speed of 20.0 m/s. It rebounds with a speed of 16.0 m/s along the same line. If the angular speed of the rod immediately after the collision is 1.14 rad/s, what was the mass of the puck
Answer:
m = 0.217 kg
Explanation:
We can solve this exercise using the conservation of angular momentum. For this the system is formed by the bar and the disk, so that the forces during the crash have been internal and the angular momentum is preserved
initial angular mount. Before impact
L₀ = L_bar + L_ disk
L₀ = I_bar w₀ + m r v₀
final angular momentum. Right after the crash
[tex]L_{f}[/tex] = I_bar wf = m r v_{f}
The moment of inertia of a bar that rotates at its ends is
I_bar = 1/12 M L
how the angular momentum is conserved
L₀ = L_{f}
I_barr w₀ + mr v₀ = I_barr w_{f} + m r v_{f}
I_bar (w₀- w_{f}) = m r (v₀- v_{f})) r
m = I_bar (w₀ - w_{f}) / r (v₀ -v_{f})
m = 1/12 M L (w₀ -w_{f} ) / r (v₀ -v_{f})
in the exercise it indicates that the initial speed of the disc is v₀ = 20 m / s and its final speed is v_{f} = -16 m / s, the negative sign is because the disc recoils
we calculate
m = 1/12 35 0.90 (0 + 1.14) / [0.30 (30- (-16))]
m = 0.217 kg
If you run the simulation a few times, you should see that for this particular pair of block and disc the block's position has the same numerical value as the disc's angular position, and the block's velocity has the same numerical value as the disc's angular velocity. Which of the following pairs of quantities must also have the same numerical values for the block and disc (assuming we use standard meter-kilogram-second units)? Select all that apply.
a. The work done by the force on the block and the work done by the torque on the disc.
b. The acceleration of the block and the angular acceleration of the disc.
c. The mass of the block and the mass of the disc.
d. The translational kinetic energy of the block and the rotational kinetic energy of the disc.
e. The momentum of the block and the angular momentum of the disc
Explanation:
C) is incorrect. The mass is equivalent to the moment of inertia in an angular formula.
The others appear all correct.
T * theta = F * r * theta = F * (r theta) = fx = work
This is the only one that needed explanation. The others should be obvious.
ASAP pls answer right and I will mark brainiest
Answer: question one: i cannot tell Question 2: waxing crescent Question 3: waxing gibbous Question 4: B
Explanation
What kind of lens is found in both a magnifying glass and a microscope
Answer:
convex lens
Explanation:
A ball is thro.d hit the grouvelocity)?
Answer:
The velocity of the ball is 3.52 m/s.
Explanation:
A projectile is any object that moves under the influence of gravity and momentum only. Examples are; a thrown ball, a fired bullet, a kicked ball, thrown javelin, etc.
Given that the ball was thrown vertically upward on the top of a skyscraper of height 61.9 m. So that the velocity can be determined by;
u = [tex]\sqrt{\frac{2H}{g} }[/tex]
Where: u is the velocity of the object, H is the height and g is the gravitational force on the object. Given that: H = 61.9 m and g = 10 m/[tex]s^{2}[/tex], then;
u = [tex]\sqrt{\frac{2*61.9}{10} }[/tex]
= [tex]\sqrt{\frac{123.8}{10} }[/tex]
u = 3.5185
The velocity of the ball is 3.52 m/s.
TIME REMAINING
58:50
Shelly tells a friend that her computer needs to be fixed because it has been producing a lot of heat and is smoking. Where
is the error in her statement?
• Heat cannot be described as having been produced.
Thermal energy cannot be produced by electronics.
Her computer should be producing a lot of heat and does not need to be fixed.
Her computer is producing thermal energy, not heat.
Mark this and return
Save and Exit
Next
Submit
Answer:
Her computer is producing thermal energy, not heat.
Explanation:
Answer:
Her computer is producing thermal energy,not heat
Explanation:
4. What is anti node?
Answer:
The position of maximum displacement in a standing wave system.
Is it true or wrong that if anyone say that, can something that is “speeding up” it means it is also have a negative acceleration? Either true or wrong justify your answer with solid reason.
Answer:
wrong
Explanation:
it depends your perspective on it
A student standing on a cliff that is a vertical height d = 8.0 m above the level ground throws a stone with velocity v0 = 15 m/s at an angle θ = 31 ° below horizontal. The stone moves without air resistance; use a Cartesian coordinate system with the origin at the stone's initial position.
Required:
With what speed, vf in meters per second, does the stone strike the ground?
Answer:
The stone strikes the ground in 14.72m/sExplanation:
The initial vertical velocity of the stone is given by:
Vyo= VSin theta
Given: V = 15m/s , theta = 31°
Vyo = 15 Sin 31
Vyo = 7.73m/s
Final vertical velocity, Vf can be determined by using kinematic equation
Vf^2 - U^2 = 2as
Vf^2 -( 7.73)^2 = 2(9.8×(-8))
Vf^2 = 59.75 + 156.8
Vf^2 = 216.6
Vf = sqrt(216.46)
Vf = 14.72m/s
Therefore,The stone strikes the ground in 14.72m/s
What is the kinetic energy of a 633.0-kg car moving at a speed of 11.2 m/s?
Answer:
39.7 kJ
Explanation:
The kinetic energy formula applies:
KE = (1/2)mv^2 = (1/2)(633.0 kg)(11.2 m/s)^2 = 39,701.76 J
The kinetic energy is about 39.7 kJ.
PLS ANSWER WILL GIVE BRAINLIEST
An elevator with a person inside weighs a total of 24,450 Newtons. an elevator that rises 12 meters in 30 seconds. How much power is needed for the elevator trip?
Answer:
9780 W
Explanation:
Power: This can be defined as the rate at which work is done. The S.I unit of power is Watt (W).
From the question,
P = W/t....................... Equation 1
Where P = power, W = work, t = time.
But,
W = F×d.............. Equation 2
Where F = force, d = distance.
Substitute equation 2 into equation 1
P = (F×d)/t................. Equation 3
Given: F = 24450 N, d = 12 m, t = 30 s.
Substitute these vales into equation 3
P = (24450×12)/30
P = 9780 W.
Hence the power needed for the elevator trip = 9780 W
Answer:
9,780WattsExplanation:
Power is defined as the rate of workdone with respect to time.
The formula for calculating power P needed by the eleveator is expressed as;
Power = [tex]\frac{workdone}{time}[/tex]
Since Workdone = Force*distance then;
[tex]Power = \frac{force * distance}{time}[/tex]
Given the weight of elevator = 24,450Newtons
distance moved by the elevator = 12m
time taken = 12seconds.
Substituting this values in the formula given will give;
[tex]Power = \frac{24,450*12}{30} \\Power = \frac{293,400}{30} \\Power = 9,780Watts\ or\ 9.78kW[/tex]
The amount of power needed for the elevator trip is 9,780Watts
A person is trying to tighten a bolt of mass 1 kg using a wrench of mass 6 kg and length
15 cm by applying a force of 12 N as shown in the diagram below. What is the torque
applied?
Answer:
0.18 Nm
Explanation:
Note: Torque is independent of the mass of a body.
From the question,
T = F×d.......................Equation 1
Where T = Torque, F = force applied to the wrench, d = length of the wrench.
Given: F = 12 N, d = 15 cm = 0.015 m
Substitute into equation 1
T = 12(0.015)
T = 0.18 Nm.
Hence the torque applied is 0.18 Nm
A 3.1 kg ball is thrown straight upward with a speed of 18.2 m/s. Use conservation of energy to calculate the maximum height the ball can reach.
Answer:
h = 16.9 m
Explanation:
When a ball is thrown upward, its velocity gradually decreases, until it stops for a moment, when it reaches the maximum height, while its height increases. Thus, the law conservation of energy states in this case, that:
Kinetic Energy Lost by Ball = Potential Energy Gained by Ball
(0.5)m(Vf² - Vi²) = mgh
h = (0.5)(Vf² - Vi²)/g
where,
Vf = Final Speed of Ball = 0 m/s (Since, ball stops for a moment at highest point)
Vi = Initial Speed of Ball = 18.2 m/s
g = acceleration due to gravity = - 9.8 m/s² ( negative for upward motion)
h = maximum height the ball can reach = ?
Therefore, using values in the equation, we get:
h = (0.5)[(0 m/s)² - (18.2 m/s)²]/(-9.8 m/s²)
h = 16.9 m
Which of the following statement(s) is
true about clipper circuits
Select one:
O a. It converts a.c to d.c always
O b. The output is clipped of some
portion of input signal
O c. It converts d.c to a.c
O d. None of these
Answer:
Explanation:
A rectifier is an electrical device that converts alternating current (AC) to direct current (DC), a process known as rectification. Rectifiers have many uses including as components of power supplies and as amplitude modulation detectors (envelope detectors) of radio signals. Rectifiers are most commonly made using solid state diodes but other type of components can be used when very high voltages or currents are involved. When only a single diode is used to rectify AC (by blocking the negative or positive portion of the waveform), the difference between the term diode and the term rectifier is simply one of usage. The term rectifier describes a diode that is being used to convert AC to DC. Most rectifier circuits contain a number of diodes in a specific arrangement to more efficiently convert AC power to DC power than is possible with only a single diode.
b. A force 100N makes an angle of Ø with the x axis and has a y component of 30 N. Find both the x and y component of the force and the angle Ø.
Answer:
Explanation:
The y component of the force is 100 sinØ . But given that y component is 30N
so 100 sinØ = 30
sinØ = 0.3
Ø = 17.5°.
X component of force = 100 cosØ
= 100 cos17.5
= 95.35 N .
Y component of force = 30 N .
Angle Ø = 17.5°.
Which of the choices is not a statement or direct application of the second law of thermodynamics? There are no 100% efficient heat engines. Heat energy naturally transfers from a high temperature substance to a low temperature substance. The change in internal energy of a system can be found by combining the heat energy added to a system minus the work done by the system. All natural processes tend toward states of increased entropy.
Answer:
Explanation:
Heat energy naturally transfers from a high temperature substance to a low temperature substance.
It is not a statement or direct application of the second law of thermodynamics.
The change in internal energy of a system can be found by combining the heat energy added to a system minus the work done by the system.
It is not a statement or direct application of the second law of thermodynamics. This statement is in accordance with first law of thermodynamics.
All the other two statements are in accordance with second law of thermodynamics.
The statement B is not a statement or direct application of the second law of thermodynamics.
Statements given to us:
(a.) There are no 100% efficient heat engines.
(b.) Heat energy naturally transfers from a high temperature substance to a low temperature substance.
(c.) The change in internal energy of a system can be found by combining the heat energy added to a system minus the work done by the system.
(d.) All natural processes tend toward states of increased entropy.
According to the Second Law of Thermodynamics:
heat transfer occurs spontaneously only from higher to lower temperature bodies.Entropy of the entire universe, as an isolated system, will always increase over time. The changes in the entropy in the universe can never be negative.So, according to the above points statement B is not a statement or direct application of the second law of thermodynamics.
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A professor sits at rest on a stool that can rotate without friction. The rotational inertia of the professor-stool system is 4.1 kg · m2 . A student tosses a 1.5-kg mass with a speed of 2.7 m/s to the professor, who catches it at a distance of 0.40 m from the axis of rotation. What is the resulting angular speed of the professor and the stool? (Assume that when the professor catches the mass, their arm is extended along a line radially outward from the axis of rotation, and the velocity of the mass is perpendicular to that line.)
Answer:
[tex]\omega=0.37 [rad/s][/tex]
Explanation:
We can use the conservation of the angular momentum.
[tex]L=mvR[/tex]
[tex]I\omega=mvR[/tex]
Now the Inertia is I(professor_stool) plus mR², that is the momentum inertia of a hoop about central axis.
So we will have:
[tex](I_{proffesor - stool}+mR^{2})\omega=mvR[/tex]
Now, we just need to solve it for ω.
[tex]\omega=\frac{mvR}{I_{proffesor-stool}+mR^{2}}[/tex]
[tex]\omega=\frac{1.5*2.7*0.4}{4.1+1.5*0.4^{2}}[/tex]
[tex]\omega=0.37 [rad/s][/tex]
I hope it helps you!
Humans living in highly populated areas are more inclined to
a. violence
b. socially isolate
C.appetite loss
d. all of the above
Answer:
they're more inclined to be violent so A
what property of an electromagnetic wave changes when the wave is encoded with analog information?
Answer:
Amplitude and Frequency
Explanation:
Analog signals are composed of continuous waves that can have any values for frequency and amplitude. These waves are smooth and curved.
Radio transmissions are a combination of two kinds of waves: audio frequency waves that represent the sounds being transmitted and radio frequency waves that "carry" the audio information. All waves have a wavelength, an amplitude and a frequency as shown in the figure. These properties of the wave allow it to be modified to carry sound information.
The two most common types of modulation used in radio are amplitude modulation (AM) and frequency modulation (FM). Frequency modulation minimizes noise and provides greater fidelity than amplitude modulation, which is the older method of broadcasting . Both AM and FM are analog transmission systems, that is, they process sounds into continuously varying patterns of electrical signals which resemble sound waves.