Answer:
(a) The magnitude of the change in internal energy is 6.623 x 10⁵ J
(b) the efficiency of the athlete is 10.94 %
Explanation:
Given;
work done by the athlete (system), W = 6.53 x 10⁴ J
the heat given off by the athlete (system), Q = 5.97 x 10⁵ J
The simple diagram below will be used to illustrate the direction of the energy flow assuming a heat engine.
Q← ⊕ →W
The work, W, points away from the system since the system does the work
The heat, Q, points away from the system since heat is given off
Apply first law of thermodynamic;
ΔU = Q + W
where;
q is the heat flowing into or out of the system
(+q if the heat is flowing into the system
(-q if the heat is leaving the system
w is the work done by or on the system
(+w if the work is done on the system by the surrounding
(-w if the work is done by the system to the surrounding
Thus, from the above explanation, the change in internal energy of the system is calculated as;
ΔU = -Q - W
ΔU = - 5.97 x 10⁵ J - 6.53 x 10⁴ J
ΔU = -6.623 x 10⁵ J
The magnitude of the change in internal energy = 6.623 x 10⁵ J
(b) the efficiency of the athlete;
[tex]Efficiency = \frac{W}{Q} \times 100\%\\\\Efficiency = \frac{6.53 \times 10^4}{5.97 \times 10^5} \times 100\%\\\\Efficiency = 10.94 \ \%[/tex]
tha motor pumps water from a well 10 m deep and projects it at a speed of 15 meters per second.the water pause ftom the pipe at a rate of 1200 kg per minute calculate the power of the motor
Answer:
4210 W
Explanation:
We'll begin by calculating the energy required in lifting the water from the depth. This can be obtained as follow:
Mass (m) = 1200 Kg
Height (h) = 10 m
Acceleration due to gravity (g) = 9.8 m/s²
Energy (E₁) =?
E₁ = mgh
E₁ = 1200 × 9.8 × 10
E₁ = 117600 J
Next, we shall determine the energy required to project the water at 15 m/s. This can be obtained as follow:
Mass (m) = 1200 Kg
Velocity (v) = 15 m/s
Energy (E₂) =?
E₂ = ½mv²
E₂ = ½ × 1200 × 15²
E₂ = 600 × 225
E₂ = 135000 J
Finally, we shall determine the power of the motor. This can be obtained as follow:
Total energy (E) = E₁ + E₂
= 117600 + 135000
= 252600 J
Time (t) = 1 min = 60 s
Power (P) =?
P = E/t
P = 252600 / 60
P = 4210 W
Therefore, the power of the motor is 4210 W.
What does Coulomb's law applies to:
1. Like charges and unlike charges
2. Charge motion
3. gravitational fields
4. moving objects
Temperature is a measure of the...
a. Total energy in a substance
b. Average kinetic energy of molecules in a substance
c. Total kinetic energy in a substance
Answer:
Temperature is a measure of the average kinetic energy of the particles in an object. So, the answer will be B.
the 120-lb woman jogs up the flight of stairsThe 120-lb woman jogs up the flight of stairs in 5 seconds. Determine her average power output.
Answer:
Power = 24.41Watts
Explanation:
Find the diagram attached
Power output = Force * distance/Time
Given
Force = 120lb
Distance = 9inches
Time = 5sec
Since
1lb = 4.4482216153 N
120lb = 120 * 4.4482216153
120lb = 533.787N
9in to meters
9in = 0.0254*9
9in = 0.2286N
Power = 533.787*0.2286/5
Power = 24.41Watts
Wave 1
WWW
m
Resulting
Wave
Wave 2
Wave 2 Phase Shift
The resulting wave has the largest possible amplitude when Wave-1 and Wave-2 are exactly in step ... their peaks both happen at the same time and their troughs both happen at the same time.
This means that Wave-1 and Wave-2 have the same frequency, and the phase shift from one wave to the other is zero.
When all of that happens, the amplitude of the resulting wave is the sum of the amplitudes of Wave-1 and Wave-2. If Wave-1 and Wave-2 have the same amplitude, then the resulting wave will have double that amplitude.
Voltages in series can be added together if the voltages are aiding each other.
a. True
b. False
Work is done when you lift an object to a certain height. If the force exerted is greater than the weight of the object, input work is greater than the output work. Where does the extra energy go?
Work is done when you lift an object to a certain height. If the force exerted is greater than the weight of the object, input work is greater than the output work. Then the extra energy goes in overcoming the gravitational acceleration and heating up of body etc
How much work can a motor with a power output of 0.70 hp do in 2 s?
Answer:
the work done by the motor is 1,044 J.
Explanation:
Given;
the output power of the motor, P = 0.7 hp
duration of the work, t = 2 s
The relationship between horse-power and watt is given as;
1 hp = 745.7 W
0.7 hp = ?
0.7 hp = 522 W = 522 J/s
The work done by the motor is calculated as;
W = Power x time
W = 522 J/s x 2 s
W = 1,044 J
Therefore, the work done by the motor is 1,044 J.
How much power is delivered to a light bulb on a 120V, 0.5A
circuit?
Answer:
60 w
Explanation:
Given :
V= 120V
I=0.5 A
Now,
power can be calculated as :
P=VI
where,
V is voltage
I is current
Now,
P=(120)(0.5)
P=60 W
Therefore, 60w power is delivered to a light
The velocity of sound is maximum in solid medium. Why?
[tex]\huge \mathscr\colorbox{yellow}{AnSwEr}[/tex]
[tex] \huge\bold{T}[/tex]he speed of sound is maximum in solids. The speed of sound depends on the density of the medium through which it travels.The higher the density of the medium, the faster the propagation of sound. Since the density of solids is greater than that of liquids and gases, sound travels faster in solids. Also, the molecules in the solid medium are closer together than in liquids or gases, which allows sound waves to travel faster through it.
[tex] \huge \fbox \red{Hope This Helps You ❤}[/tex]
A converging lens is also known as a
•convex
•concave
•double
•refracted
Answer:
Convex lens
Explanation:
hope this helps
Answer:
convex lens
Explanation:
A converging lens is also called a convex lens because it makes parallel light rays passing through it Bend Inward and meet at a spot just beyond the lens known as the focal point.
4. How much milk at 5° C needs to be added to 250 g of coffee at 90° C to make the coffee drinkable at 60° C?
Answer:
dino :)
Explanation:
Which property of matter determines the amount of inertia an object has? Matter’s ________
Answer:
Mater's Mass is the Answer
effieiency of simple machine is always less than 100% why
Answer:
efficiency of a machine is less than 100% because some part is energy is utilized to overcome some opposing forces like friction which is wasted as heat ,sound energy etc
Explanation:
Compared to its weight on Earth, a 5kg object on the moon will weigh
The same amount
Less
More
Answer:
Less
Explanation:
Weight is a force measurement. The object's mass is 5kg not its weight. To find its weight you have to take the mass of an object and multiply it by the acceleration of gravity. The acceleration of gravity is greater on earth than on the moon so therefore the object will weigh less on the moon.
What kind of model is shown below?
о
A. Experimental model
O B. Computer model
O C. Mathematical model
O D. Physical model
Answer:
.....where's the model-
A camera lens used for taking close-up photographs has a focal length of 22.0 mm. The farthest it can be placed from the film is 32.9 mm. What is the closest object that can be photographed
Answer:
p = 6.64 cm
Explanation:
For this exercise we use the equation of the constructor
[tex]\frac{1}{f} = \frac{1}{p} + \frac{1}{q}[/tex]
where f is the focal length, p and q are the distance to the object and the image, respectively
They tell us the focal length f = 2.2 cm and that the image as far as it can go is q = 3.29 cm, let's find the position of the object that creates this image
[tex]\frac{1}{p} = \frac{1}{f} - \frac{1}{q}[/tex]
1 / p = 1 / 2.2 - 1/3.29
1 / p = 0.15059
p = 6.64 cm
therefore the farthest distance from the object is 6.64 c
When a light bulb is connected to a 4.5 V battery, a current of 0.16 A passes through the bulb filament. What is the resistance of the filament
Answer:
R = 28.125 ohms
Explanation:
Given that,
The voltage of a bulb, V = 4.5 V
Current, I = 0.16 A
We need to find the resistance of the filament. Using Ohm's law,
V = IR
Where
R is the resistance of the filament
So,
[tex]R=\dfrac{V}{I}\\\\R=\dfrac{4.5}{0.16}\\\\R=28.125\ \Omega[/tex]
So, the resistance of the filament is equal to 28.125 ohms.
You drive past a potential parking space in center city. Your new car is travelling at 85% the speed of light. If your car is 6.0 m long (which you measured the day you bought it) and you observe the space to be 3.0 m, should you try to park? Why is your friend on the sidewalk (who hasn't studied relativity) so sure that you can park? How does the situation appear to him?
Answer:
We should not try to park the car because its rest length is greater than the space available.
The car seems to be approximately equal to the friend (L = 3.16 m). Due to this reason he is sure to park.
Explanation:
We should not try to park the car because its rest length is greater than the space available.
The friend is sure about parking because the car appears short in length to him. For this, we will solve Einstein's length contraction formula from theory of relativity:
[tex]L = L_o\sqrt{1-\frac{v^2}{c^2}}[/tex]
where,
L = Relative length observed by friend = ?
L₀ = rest length = 6 m
v = relative speed = 85% of speed of light = 0.85c
Therefore,
[tex]L = (6\ m)\sqrt{1-\frac{(0.85c)^2}{c^2}}[/tex]
L = 3.16 m
Hence, the car seems to be approximately equal to the friend. Due to this reason he is sure to park.
A space probe is launched from Earth headed for deep space. At a distance of 10,000 miles from Earth's center, the gravitational force on it is 435 lb. What is the size of the force when it is at 20,000, 30,000, and 100,000 miles from the earth's center?
Answer:
2
Explanation:
Two people that have identical weight are holding onto a massless pole while standing on horizontal frictionless ice. 1)If the guy on the left starts to pull on the pole, where do they meet
Answer:
Explanation:
From the missing image attached below, it is obvious that there no external force. This implies that they cannot change their position by merely just pulling the ropes. As a result, there will be no movement and no net force will exist.
So, if there is no external force;
The center of mass of the two people is:
[tex]X_{cm}= \dfrac{m_1x_1+m_2x_2}{m_1+m_2} \\ \\ X_{cm}= \dfrac{m(-3m)+m(+3m)} {m+m}\\ \\ X_{cm}= \dfrac{0}{2m} \\ \\ X_{cm} =0[/tex]
Thus, In the system, no movement occurs and all forces remain the same.
the electrochemical equivalent of silver is 0.0012g/c if 36.0g of silver is to be deposited by electrolysis on a surface by passing a steady current for 5 minutes, the current must be?
Answer:
100 A.
Explanation:
From the question given above, the following data were obtained:
Electrochemical equivalent (Z) = 0.0012 g/C
Mass (M) = 36 g
Time (t) = 5 mins
Current (I) =?
Next, we shall determine the charge. This can be obtained as follow:
Electrochemical equivalence (Z) = 0.0012 g/C
Mass (M) = 36 g
Charge (Q) =.?
M = ZQ
36 = 0.0012 × Q
Divide both side by 0.0012
Q = 36 / 0.0012
Q = 30000 C
Next, we shall convert 5 mins to s. This can be obtained as follow:
1 min = 60 s
Therefore,
5 mins = 5 × 60
5 mins = 300 s
Finally, we shall determine the current. This can be obtained as shown below:
Charge (Q) = 30000 C
Time (t) = 300 s
Current (I) =?
Q = It
30000 = I × 300
Divide both side by 300
I = 30000 / 300
I = 100 A
Therefore, the current is 100 A.
How can spectroscopy and infrared technology be useful in space? (5 points)
a.)They can enhance speed by making spacecraft fuel more efficient.
b.) They can measure magnetic fields produced by astronomical bodies.
c.) They can provide an emergency escape to the astronaut from a space center.
d.) They can determine the elements that make up the surface of astronomical bodies.
Answer:
B
Explanation:
i took the test
Determine whether the sampling is dependent or independent. Indicate whether the response variable is qualitative orquantitative.
A city council randomly selects 1000 married couples from a certain city and records the number ofwomen who are in favor of a new football stadium and the number of men who are in favor.
a. quantitative, dependent
b. qualitative, dependent
c. qualitative, independent
d. quantitative, independent
Answer: D. Quantitative, Independent
Explanation:
Based on the information given in the question, the response variable is quantitative while the sampling is independent.
Independent samples refers to the samples which are randomly selected in such a way that the observations aren't dependent on the values of the other observations.
Quantitative variables refers to the numerical variables which can be in form of percents, counts, or numbers.
Since the city council randomly selects 1000 married couples from the city, then the answer is "Quantitative, Independent".
Try to shorten the long string and talk once again with one of your family members, how did the length of the string affect the quality of the sound produced?
Answer:
Explanation:
The length of the string determines the frequency of the sound waves. Shorter length strings will cause the string to vibrate faster which causes faster frequency and a higher pitch. Longer length strings have the opposite effect, in which frequency is slowed down causing lower pitch. This higher pitch creates a perceived brightness of the sound which can be categorized as being a better sound quality than that of a lower-pitched message. Therefore, we can say that yes, it does affect the sound produced.
As a new electrical engineer for the local power company, you are assigned the project of designing a generator of sinusoidal ac voltage with a maximum voltage of 120 V. Besides plenty of wire, you have two strong magnets that can produce a constant uniform magnetic field of 1.5 T over a square area with a length of 10.2 cm on a side when the magnets are separated by a distance of 12.8 cm . The basic design should consist of a square coil turning in the uniform magnetic field. To have an acceptable coil resistance, the coil can have at most 400 loops.
What is the minimum rotation rate of the coil so it will produce the required voltage? Express your answer using two significant figures.
Answer:
The rotation rate is 15.3 rad/s.
Explanation:
maximum voltage, V = 120 V
Magnetic field, B = 1.5 T
length, L = 10.2 cm
width, W = 12.8 cm
Number of loops, N = 400
Let the rate of rotation is w.
The maximum voltage is given by
V = N B A w
120 = 400 x 1.5 x 0.102 x 0.128 x w
w = 15.3 rad/s
A red laser from the physics lab is marked as producing 632.8-nm light. When light from this laser falls on two closely spaced slits, an interference pattern formed on a wall several meters away has bright fringes spaced 6.00 mm apart near the center of the pattern. When the laser is replaced by a small laser pointer, the fringes are 6.30 mm apart.
Required:
What is the wavelength of light produced by the pointer?
Answer:
Wavelength = [tex]\lambda_p = 3.986 * 10^{-6}[/tex] m
Explanation:
As we know
Fringe width (w) = [tex]\frac{D*\lambda}{d}[/tex]
where
[tex]\lambda[/tex] is the wavelength
D is distance between source and screen
d is the distance between two slits
[tex]\frac{D}{d} = \frac{y}{\lambda}[/tex]
[tex]\frac{D}{d} = \frac{y_r}{\lambda_r} = \frac{y_p}{\lambda_p}\\\frac{y_r}{\lambda_r} = \frac{y_p}{\lambda_p}\\\lambda_p = \frac{y_p* \lambda_r}{y_r} \\\lambda_p =\frac{6.30 * 10^{-3} * 632.8 * 10^{-9}}{6 *10^{-3}} \\\lambda_p = 3.986 * 10^{-6}[/tex]m
What do interplanetary space missions study?
the moon
stars in other galaxies
planets in the solar system
the sun
Answer:
C. Planets in the solar systemExplanation:
The one above is incorrect, and I know this is late. Even if it doesn't help you I hope it helps people in the future! YES I AM TALKING ABOUT YOU FUTURE PEOPLE!! I know this is the answer because I have taken 5.11 Quiz: Uncrewed Spacecraft in K12. There will only be the questions and correct answers below.
1. Which planetary body was Spirit designed to explore?
Mars.
2. What is the name of the most distant manmade object in space? (Credit: shathaadnan64/lak521)
Voyager 1.
3. Which group was designed to study Saturn? (Credit: Brainly User/snowballandtigoya1xa
Voyager 1, Huygens, and Cassini.
4. Why are scientists interested in exploring Mars?
Possible evidence of life.
5. What do interplanetary space missions study?
Planets in the solar system.
Have an amazing day!!
PLEASE HELPPPPPP!!!!!!
Explanation:
Since gravitational forces are inversely proportional to the square of their distances, tripling the distance means the reduction of the force by a factor of 9. That means the force experienced by the two objects will be 1/9 smaller than before.
La velocidad del sonido en el aire es 340 m/s. Desde que se produjo el relámpago hasta que se oyó el trueno han transcurrido 8 s. ¿A qué distancia se produjo la descarga eléctrica?
Answer:
Distancia = 42.5 metros
Explanation:
Dados los siguientes datos;
Velocidad del sonido = 340 m/s
Tiempo = 8 segundos
Para encontrar la distancia desde la que se escuchó el sonido;
Distancia = velocidad/tiempo
Sustituyendo en la fórmula, tenemos;
Distancia = 340/8
Distancia = 42.5 metros