Answer: A
Explanation:
A source of heat at 1000 K transfers 1000 kW of power to a power generation device, while producing 400 kW of useful work. Determine the second law efficiency of the system, if the environment is at 300 K.
Answer:
The value is [tex]\eta _2 = 0.57[/tex]
Explanation:
From the question we are told that
The temperature of the heat source is [tex]T_s = 1000 \ K[/tex]
The amount of power transferred is [tex]P_s = 1000 \ kW = 1000 *10^{3} \ W[/tex]
The work produced is [tex]W = 400 \ kW[/tex]
The temperature of the environment [tex]T_e = 300 \ K[/tex]
Gnerally the Carnot efficiency of the system is mathematically represented as
[tex]\eta_c = 1 -\frac{T_e}{T_s}[/tex]
=> [tex]\eta_c = 1 -\frac{300}{1000}[/tex]
=> [tex]\eta_c = 0.7[/tex]
Generally the first law efficiency of the system is mathematically represented as
[tex]\eta _1 = \frac{W}{P_s}[/tex]
=> [tex]\eta _1 = \frac{400}{1000}[/tex]
=> [tex]\eta _1 = 0.40[/tex]
Generally the second law efficiency of the system is mathematically represented as
[tex]\eta _2 = \frac{\eta_1}{\eta_c}[/tex]
=> [tex]\eta _2 = \frac{0.4}{0.7}[/tex]
=> [tex]\eta _2 = 0.57[/tex]
Three people are trying to move a box. Which set of forces will result in a net
force on the box of 20 N to the right?
A.
B.
O C.
O D.
18 N
55 N
55 N
6 N
← PREVIOUS
1₂
28 N
16 N 17 N
0
10 N
17 N
$
16 N
-
20 N
6 N
Correct answer is A
Answer:
A
Explanation:
18-28=10
10+10=20
20N to the right
A toy car in the figure below runs off the edge of a table that is h = 1.36 m high. The
car lands d= 0.88 m from the base of the table. How fast was the car going on the
table?
The toy car was going at a speed of 1.66 m/s on the table.
When the toy car runs off the edge of the table, it travels vertically as well as horizontally and it is an example of a horizontal projectile from a height.
The distance covered vertically will be equal to the height of the table which is 1.36m. And horizontal distance is given as d.
Vertical distance = H = 1.36m
Horizontal distance = d = 0.88m
Now, we for a free-falling body, in
Speed in vertical direction = u = 0 m/s
Distance = h = 1.36
Using the second equation of motion,
h = ut + 1/2gt²
Put in the value, we get
1.36 = (0)t + 1/2(9.8)t²
t² = 1.36/4.9
t² = 0.278
t = 0.53 seconds
Now distance traveled in a horizontal direction is given by
Distance in horizontal direction = Speed on table × time of travel
Put in the value, we get
0.88 = V × 0.53
V = 0.88/0.53
V = 1.66 m/s
So, the toy car was going at a speed of 1.66 m/s on the table.
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A car is stopped for a traffic signal. When the light turns green,
the car accelerates, increasing its speed from 0 to 5.20 m/s in
0.832 s. What are the magnitudes of (a) the linear impulse and
(b) the average total force experienced by a 70.0-kg passenger
in the car during the time the car accelerates?
Answer:
Impulse, p = 364 N·s
Force F = 437.5 N
Explanation:
First some definitions:
Part (a)
Since the car is initially at rest, its initial momentum is 0.
When the car reaches a velocity of 5.20 m/s, the momentum experienced by a 70 kg passenger is
Δv = 5.20 - 0 = 5.20 m/s
p = 70 kg x 5.20 m/s = 50.3248 kg m/s = 364 N·s
p = 384 N.s
Part (b)
Force is given by F=m(Δv/Δt) = 70 kg x (5.20 m/s / 0.832 s) = 437.5 N
F = 437.5 N
if A.B=A.C
does this imply that B must be equal to c ?
I need answer with example please
Answer:
Yes
Explanation:
[tex]Consider\ three\ variables\ a,b\ and\ c.\\If,\\ab=ac\\a*b=a*c\\We\ may\ now\ divide\ the\ LHS\ and\ RHS\ by\ a,\\Hence,\\\frac{a*b}{a} =\frac{a*c}{a}\\Hence,\\b=c[/tex]
[tex]Ex: \\Consider\ a=5, b=6.\\Hence\ if,\\a*b=a*c\\5*6=5*c\\Hence,\\30=5c\\Hence, c=\frac{30}{5}\\c=6\\As\ b\ also\ equals\ to\ 6,\\b=c[/tex]
As a 3.0 kg bucket is being lowered into a 10 m deepwell, starting from top, the tension in the rope is 9.8 N. theacceleration of the bucket will be:____________A) 6.5 m/s2 downwardB) 9.8 m/s2 downwardC) zeroD) 3.3 m/s2 upwardE) 5.6 m/s2 upward
Answer:
A) 6.5 m/s²
Explanation:
Mass of the bucket, m = 3.0 kg
depth of the well, d = 10 m
tension on the rope, T = 9.8 N
The net downward force on the bucket is given as;
T = mg - ma
where;
a is downward acceleration of the bucket
9.8 = (3 x 9.8) - 3a
9.8 = 29.4 - 3a
3a = 29.4 - 9.8
3a = 19.6
a = 19.6 / 3
a = 6.53 m/s² downwards
Therefore, the acceleration of the bucket is 6.53 m/s² downwards
A 120V AC signal is available at the wall port. You are required to convert it to a constant DC voltage of 12V for a laptop to operate. What are the three electrical components you will be using to achieve the same? Name the components in order and the function it performs.
Answer:
The following components shall be used in given order:
1. Step Down Transformer 2. Diode as Rectifier 3. Capacitor
Explanation:
The following components shall be used in given order:
1. Step Down Transformer 2. Diode as Rectifier 3. Capacitor
1.STEP DOWN TRANSFORMER:
The step down transformer is first used to convert the 120 V AC signal into 12 V AC signal. Because the output required is of 12 V.
2.DIODE AS RECTIFIER:
Now, the PN Junction diode is used as a rectifier to convert the 12 V AC signal to 12 V DC signal.
3.CAPACITOR:
Now, the output is in waveforms. So, in order to linearize it in the form of DC current, we use capacitor. The main function of capacitor is to smoothen the signal into a straight line.
How much work is done by an applied force to lift a 15-Newton 3Meters and 9.8?
Given=
Unknown=
Formula=
Solution=
Answer=
The work done by the applied force of 15 Newton to lift the object up 3 meters is 45 J
W = F d
W = Work done
F = Force
d = Distance
F = 15 N
d= 3 m
W = 15 * 3
W = 15 J
Work done is the amount of force required to move an object. It is denoted by W. Its unit is usually Joules.
Therefore, the work done to lift the object is 15 J
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The two ends of an iron rod are maintained at different temperatures. The amount of heat that flows through the rod by conducting DOES NOT depend on
Answer:
D mass of the iron rod
Explanation:
A) the length of the iron rod.
B) the thermal conductivity of iron.
C) the temperature difference between the ends of the rod.
D) the mass of the iron rod.
E) the duration of the time interval
The amount of heat that will flow through an iron rod whose two ends are maintained at different temperatures would depend on the thermal conductivity of the iron, the temperature difference between the two ends, the length of the iron rod, and the duration of flow of heat.
The thermal conductivity of any material is an indication of the ability of the materials to conduct heat. The higher the thermal conductivity, the higher the amount of heat a material can conduct within a specified period. Hence, the amount of heat that will flow through the iron rod depends on its thermal conductivity.
The temperature difference between two solid materials depends on the amount of heat that will flow across the materials by conduction. The higher the difference, the more the amount of heat that will flow. Hence, the amount of heat that would be conducted depends on the temperature difference between the two ends of the iron rod
The amount of heat that would move my conduction also depends on the distance that would be traveled by the heat. Due to heat loss to the surrounding, the shorter the distance, the more the heat and vice versa. Hence, the amount of heat that will flow through an iron rod depends on the length of the iron rod.
The duration of flow also dictates the amount of heat that will flow between two regions by conduction. The more the duration, the more the heat, provided that other conditions remain constant.
The only option that the amount of heat that would be conducted does not depend on is the mass of the iron rod.
The correct option is D.
In winter morning, as soon as we wake the air inside the room is cold but if up, the out and return to the same room, we we goo feel warm, why?
Answer:
it is all because of nature
F x T = m (Vf - Vi)
in this equation what does the M stand for
Answer:
m = mass [kg]
Explanation:
This equation is characteristic of the amount of motion and momentum.
[tex]F*t = m*(v_{f}-v_{i})[/tex]
where:
F = force [N] (units of Newtons)
t = time = [s]
m = mass [kg]
Vf = final velocity [m/s]
Vi = initial velocity [m/s]
Now using the units and placing them in the equation above.
[tex][N]*[s] = [kg]*(m/s-m/s)\\[/tex]
[tex][N]=[kg*m/s^{2} ][/tex]
Now replacing:
[tex][kg*m/s^{2}]*[s]=[kg*m/s][/tex]
The s² is cancelled with the s, therefore.
[tex][kg*m/s]=[kg*m/s][/tex]
At the mail racing championship in England, the winner moved at an average velocity of 2.4 mm/s [ford] for 140 s. Determine the winning snail's displacement during this time interval. [
Answer:
Explanation: 1.2 mm
Time= 140 sec
Initial Velocity= 0
Average Velocity= 2.4 mm/s
Displacement= 0.5* (2.4/140) *140 = 1.2 mm
The subjective perception of the frequency of sound is called ?
Answer: The subjective perception of the frequency of sound is called a Pitch
Explanation: Because the Pitch has a lowest and highest of a sound fundamental
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Answer:
Question 4 is actually Acceleration
The time taken by a mass projected vertically
upwards to reach the maximum height (with air
resistance not neglected) is 10 sec. The time of
descent of the mass from the same height will be
Answer:
10s
Explanation:
The time to get to the maximum would be the same as the time to get down to the maximum unless somehow gravity’s changes during the duration it goes up to and from maximum height.
10. The Earth's radius is about 6370 km. An object that has a mass of 20 kg is taken to a
height of 160 km above the Earth's surface. How much does the object weigh at this
height?
Answer:
Weight:
P =m·g₁ = 20·9.55 = 191 H
Explanation:
Given:
R = 6 370 км = 6 370·10³ m
m = 20 kg
h = 160 km = 160·10³ m
g = 9.8 m/s²
____________________
P - ?
Acceleration of free fall at the Earth's surface:
g = G*M / R² (1)
Acceleration of free fall at height h:
g₁ = G*M / (R + h) ² (2)
Divide (1) by (2):
g / g₁ = ((R + h) / R)²
g / g₁ = ( 1 + h / R)² = ( 1 + 160 / 6 370)² ≈ 1.026
g₁ = g / 1.026 = 9.8 / 1.026 ≈ 9.55 m/s²
Weight:
P =m·g₁ = 20·9.55 = 191 H
the distance between my home to school is 3 km and 240 m. what is the distance in km,m and dm
Answer:
km = 3.24
m = 3,240
dm = 32,400
Explanation:
km = 1000m
m = 10dm
Explanation:
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a sphere with a radius of 8cm carries a uniform volume charge density of 1.5 find the magnitude of the electric field
Answer:
E = 5.65 x 10¹⁰ N/C
Explanation:
First we need to find the total charge on the sphere. So, we use the following formula for that purpose:
[tex]q = \sigma V\\[/tex]
where,
q = total charge on sphere
V = Volume of Sphere = [tex]\frac{4}{3} \pi r^3 = \frac{4}{3} \pi (0.08\ m)^3 = 0.335\ m^3[/tex]
σ = volume charge density = 1.5 C/m³
Therefore,
[tex]q = (0.335\ m^3)(1.5\ C/m^3) \\q = 0.502 C[/tex]
Now, we use the following formula to find the electric field due to this charged sphere:
[tex]E = \frac{kq}{r^2}[/tex]
where.
E = Electric Field Magnitude = ?
k = Coulomb's Constant = 9 x 10⁹ N.m²/C²
r = radius of sphere = 8 cm = 0.08 m
Therefore,
[tex]E = \frac{(9\ x\ 10^9\ Nm^2/C^2)(0.502 C)}{(0.08\ m)^2}\\\\[/tex]
E = 5.65 x 10¹⁰ N/C
Damage to internal organs will present as pain associated with a particular surface area of the body. Why would something like irritation to the diaphragm, which is between the thoracic and abdominal cavities, feel like pain in the shoulder or neck?
If a mass of an object is 20 kg on earth, so what will be its weight?
Answer:
200 Newton
Explanation:
Weight is the force with which earth pulls the object.
W = M× g
where m is mass and g is acceleration due to gravity whose value is approximately 10 Newton
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An 877 kg drag race car accelerates from rest to 116 km/h in 0.951 s. What change in momentum does the force produce? Answer in units of kg. m/s.
Answer:
The change in momentum is 28265.71 kg-m/s.
Explanation:
Given that,
Mass of a car, m = 877 kg
Initial velocity of the car, u = 0 (at rest)
Final velocity of the car, v = 116 km/h = 32.23 m/s
Time, t = 0.951 s
We need to find the change in momentum produced by the force. It can be calculated as the difference of final momentum and the initial momentum.
[tex]\Delta P=m(v-u)\\\\=877\times (32.23-0)\\\\=28265.71\ kg-m/s[/tex]
So, the change in momentum is 28265.71 kg-m/s.
Which of the following will increase if the voltage in a circuit is increased?
Check all that apply
A.Magnetic force
B. Resistance
C. Current
D. Heat produced by the circuit
Answer:
D i think (apologies if incorrect)
PLZZZ I will give brainliest. A ball that contains mechanical energy is rolled across the floor. You notice the ball is slowing down. If the ball started with 20 units of energy, explain how much energy would there be when the ball comes to a complete stop? How can you tell?
Answer: because of friction it will stop rolling completly
Explanation:
which of the following could be cause of a irregular systolic reading
1. The one-way valves are not working
2 Blood is not flowing properly from the veins to the heart
3 Carbon dioxide and oxygen are mixing in the blood
4. The left ventricle is having difficulty contracting
PLEASE HELP ME!! I NEED ANSWERS ASAP!!!!
Answer:
I do not know the answer because not all of the information is there.
Explanation:
Answer:
Beep Beep
Explanation:
What is the voltage of a circuit that has a current of 3.7 amps and a resistance of 1.5 ohms.
Answer:
V = 5.55 volts
Explanation:
Given that,
Current, I = 3.7 A
Resistance, R = 1.5 ohms
We need to find the voltage of the circuit. Let V is the voltage. We can find it using Ohm's law as follows :
V = IR
Substituting all the values, we get :
[tex]V=3.7\times 1.5\\\\=5.55\ V[/tex]
So, the voltage of the circuit is 5.55 V,
A powerful missile reaches a speed of 5 kilometers per second in 10 seconds after its launch. What is the average acceleration of the missile during this period?
A. 0.2 meters/second2
B. 0.4 centimeters/second2
C. 0.5 meters/second2
D. 0.5 kilometers/second2
Answer:
D option
Explanation:
please mark me brainliest and 5 star
Answer:
D. 0.5 km/s2
Explanation:
The world record for a woman running a marathon is approximately 2.25 hours. If a marathon's distance is 26.2 miles (42164.81 meters) and it is run
in a southeast direction, what is the velocity?
60 mph southeast
0.09 mph southeast
Omph southeast
11.6 mph southeast
Answer:
11.6mph South East
Explanation:
Given parameters:
Time = 2.25hrs
Displacement = 26.2miles south east
Unknown:
Velocity = ?
Solution:
Velocity is the displacement divided by the time taken. It is a vector quantity with both magnitude and direction.
Now;
Velocity = [tex]\frac{displacement}{time taken}[/tex]
Velocity = [tex]\frac{26.2}{2.25}[/tex] = 11.6mph South East
Answer:
11.6mph south east.
Which wave has high enough energy to cause damage to skin and sometimes cancer?
Answer: All UV can have harmful effects on biological matter (such as causing cancers) with the highest energies causing the most damage.
Explanation:
Dale and Alex push on opposite sides of a couch. Dale pushes to the left with a force of 40 N, while Alex pushes to the right with a force of 32 N. If the
couch has a mass of 28 kg, what is the acceleration of the couch?
A. 2.6 m/s^2 right
B. 2.6 m/s^2 left
C. 0.3 m/s^2 left
D. 0.3 m/s^2 right
0.3 m/s^2 left will be the acceleration of the couch.
we have given in the statement
force towards left 40 N
force towards right 32 N
net force = 40-32 = 8 N towards left
couch mass = 28 kg
now we will use newtons 2nd law to find acceleration
F=ma, here f is force m is mass a is acceleration
a=F/m
a=8/24
a=0.285 ≅ 0.3 N
An object's rise in velocity rate is referred to as acceleration. It is a vector quantity that is sign-sensitive, and the route shift and body speed variance establish the sign norm. it's unit is m/s^2To know more about acceleration visit : https://brainly.com/question/3046924
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0.3 m/s squared left Answer:
Explanation: