Answer:
178.5 Hz
Explanation:
Given that a car approaches a train station with a speed of 24 m/s. A stationary train at the station sounds its horn which has a frequency of 166 Hz. What frequency of sound is heard by the car's driver ?
Solution
Using doppler effect formula
F = f ( V/ V- v)
Where F = frequency of sound heard by the car
f = train frequency
V = speed of sound
v = car speed
F = 166 ( 343 ÷ ( 343 - 24 ) )
F = 166 ( 343 / 319 )
F = 166 × 1.0752
F = 178.489 Hz
F = 178.5 Hz
Therefore, the frequency of sound heard by the observer in the car is 178.5 Hz approximately.
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]
A cheetah can run at a maximum speed
106 km/h and a gazelle can run at a maxi-
mum speed of 75.6 km/h.
If both animals are running at full speed,
with the gazelle 63.4 m ahead, how long before
the cheetah catches its prey?
Answer in units of s.
Answer:
Cheetah speed:
Its position at time t is given by
(1)
Gazelle speed:
the gazelle starts S0=96.8 m ahead, therefore its position at time t is given by
(2)
The cheetah reaches the gazelle when . Therefore, equalizing (1) and (2) and solving for t, we find the time the cheetah needs to catch the gazelle:
(2) To solve the problem, we have to calculate the distance that the two animals can cover in t=7.5 s.
Cheetah:
Gazelle:
So, the gazelle should be ahead of the cheetah of at least
Explanation: try these steps to answer
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.
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.
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 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.
what is the frequency of a wave traveling at 340 m/s with a wavelength of 125 m
Answer:
I think it's really cool
As the shuttle bus comes to a sudden stop to avoid hitting a dog. It accelerates unfirmly at -4.1m/s^2 as it slow down from 9.0m/s to 0.0m/s. Find the interval of acceleration for the bus
The interval of acceleration of the bus will be 2.19 seconds.
What is acceleration?An object is considered to have been accelerated if its velocity changes. Depending on whether an object is moving faster, slower, or in a different direction, its velocity may change.
Examples of acceleration include a falling apple, the moon orbiting the earth, and a car that has stopped at a stop sign. These examples demonstrate how acceleration occurs whenever a moving object modifies its direction, speed, or both.
Acceleration is a vector quantity.
SI unit of acceleration is m/s.
According to the question, the given values are :
Acceleration, a=-4.1 m/s²
Initial velocity, u=9.0 m/s and,
Final velocity, v=0 m/s
By using Equation of motion, i.e.,
v=u+at
⇒0 m/s=9m/s+(-4.1 m/s²)(t)
⇒-9 m/s=-4.1 m/s²×t
t=(-9 m/s)/(-4.1 m/s²)
t= 2.19 seconds.
Hence, the time interval of acceleration of the bus will be 2.19 seconds.
To get more information about acceleration :
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Find the object's positions x1 , x2 , x3 , and x4 at times t1=2.0s , t2=4.0s , t3=13s , and t4=17s .
Answer:
Explanation:
x₁(2.0) = 4 m
x₂(4.0) = 7 m
x₃(13) = 9 m
x₄(17) = 0 m
Which of the graphs describes the motion of a person who first rode her bicycle at constant speed and then rested?
Answer:
Its graph 1
Explanation:
She started at the origin and kept riding her bike until she stopped which causes the line to go staright because she's not moving.
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:
take a look carefully hope it will help u
What do scientists do? A. They use their knowledge to make public policy. B. They make ethical decisions for the government. C. They gather evidence to help answer questions. D. They discover as many facts as they can.
Answer:
Explanation:
C
Elizabeth was a brilliant lawyer until she began hearing voices and seeing things that are not there. She also has trouble with her thought processes and making sense in her speech. She is suffering from:
A. fugue
B. schizophrenia
C. anxiety
D. dissociation
Answer:
B) Schizophrenia
Explanation:
Hope this helps!
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
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
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:
Consider the vector below. Determine its length and direction. Vector: 2i+11j+5k2i+11j+5k Magnitude: Direction (unitized):
Answer:
Magnitude: [tex]\|\vec v\| = 5\sqrt{6}[/tex], Direction (unitized): [tex]\vec u = \frac{\sqrt{6}}{6}\,\hat{i} + \frac{11\sqrt{6}}{12}\,\hat{j}+\frac{5\sqrt{6}}{12}\,\hat{k}[/tex]
Explanation:
Let [tex]\vec v = a\,\hat{i}+b\,\hat{j}+c\,\hat{k}[/tex]. The magnitude of the vector is represented by the Pythagorean formula:
[tex]\|\vec v\| = \sqrt{a^{2}+b^{2}+c^{3}}[/tex] (1)
And the direction is represented by the direction cosines, measured in sexagesimal degrees, that is:
[tex]\theta_{x} = \cos^{-1} \frac{a}{\|\vec v\|}[/tex] (2)
[tex]\theta_{y} = \cos^{-1} \frac{b}{\|\vec v\|}[/tex] (3)
[tex]\theta_{z} = \cos^{-1}\frac{c}{\|\vec v\|}[/tex] (4)
If we know that [tex]a = 2[/tex], [tex]b = 11[/tex] and [tex]c = 5[/tex], then the magnitude and directions of the vector are, respectively:
[tex]\|\vec v\| = \sqrt{2^{2}+11^{2}+5^{2}}[/tex]
[tex]\|\vec v\| = 5\sqrt{6}[/tex]
The direction can be represented by the following unit vector:
[tex]\vec u = \frac{\vec v}{\|\vec v\|}[/tex] (5)
[tex]\vec u = \frac{2\,\hat{i}+11\,\hat{j}+5\,\hat{k}}{2\sqrt{6}}[/tex]
[tex]\vec u = \frac{\sqrt{6}}{6}\,\hat{i} + \frac{11\sqrt{6}}{12}\,\hat{j}+\frac{5\sqrt{6}}{12}\,\hat{k}[/tex]
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:
A 35 kg child goes down a playground that is inclined at an angle of 27.5 degrees above the horizontal. Find the acceleration if the child given that the coefficent of kinetic friction between the child and the slide is 0.415.
Answer:
4.16m/s²
Explanation:
According to Newtons second law;
[tex]\sum Fx = ma_x\\Fm - Ff = ma_x\\W sin\theta - \mu R cos \theta = ma_x\\mg sin\theta - \mu mg cos\theta = ma_x\\[/tex]
Fm is the moving force
[tex]\mu[/tex] is the coefficient of kinetic friction between the child and the slide
m is the mass
g is the acceleration due to gravity
a is the acceleration of the child
Substitute the given values and get the acceleration as shown;
35(9.8)sin27.5 - 0.415(35)(cos27.5) = 35a
158.38-12.88 = 35a
145.49 = 35a
a = 145.49/35
a = 4.16m/s²
Hence the acceleration of the body is 4.16m/s²
If a radio wave has speed 3.00 *10^8 m/s and frequency 94.7 MHz, what is its wavelength?
[tex]We \: know \: that, \: c = λv \\ thus \: \: λ = \frac{c}{v} = \frac{3 \times {10}^{8} \: m {s}^{ - 1} }{94.7 \times {10}^{6} } \\ = 3.16789863≈3.17 \: m[/tex]
Hope this helps :)
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 solid disc is rolling without slipping at constant speed on a horizontal surface. What is the ratio of its rotational kinetic energy to its translational kinetic energy
Answer:
2/7
Explanation:
The Rotational Kinetic Energy is given as RKE = 1/2 * I * w², where
w = v/R and
I = 2/5mR²
The Translational Kinetic Energy is given as TKE = 1/2 * m * v²
RKE = 1/2 * 2/5mR² * (v/R)²
RKE = 1/2 * 2/5mR² * v²/R²
RKE = 1/5mv²
To get the ratio, we use the relation
RKE / (TKE + RKE)
and thus, we have
1/5mv² / (1/2mv² + 1/5mv²)
1/5mv² / 7/10mv²
1/5 ÷ 7/10
1/5 * 10/7
2/7
Therefore, the ratio of RKE to TKE is 2/7
What will happen to the ice cubes in the two spoons? How will they be different?
Answer: the ice cube to melt more quickly on the metal block than on the wooden block.
Explanation:
Use the illustration below to answer Question #2:
The color spectrum above shows the wavelength range for each color of light. Based on this information, which statement about the colors at each end is true? (AKS 9a, DOK 1)
Red has the longest wavelength and the lowest frequency
Red has the shortest wavelength and the lowest frequency
Violet has the longest wavelength and the lowest frequency
Violet has the shortest wavelength and the lowest freq
Violet has the shortest wavelength and the lowest frequency.
When the entire spectrum of red visible light passes through a prism the wavelengths are separated into the colors of the rainbow because each color is a different wavelength. Violet has the shortest wavelength at about 380 nanometers and red has the longest wavelength at about 700 nanometers.
Visible light travels at 300,000 km/s and can be separated into 7 colors. From the longest wavelength, they are red, orange yellow green blue indigo, and violet. To clarify color is the eye's perception of different wavelengths of electromagnetic light. When it comes to visible light, the color with the highest frequency violet also has the highest energy. The lowest frequency of visible light red has the lowest energy.
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A hollow aluminum sphere with outer diameter 10.4 cm has a mass of 746 g .What is the sphere's inner diameter?Express your answer with the appropriate units.Din=
Answer: the sphere's inner radius is 4.21 cm so the Inner diameter is 8.42 cm
Explanation:
Given that;
mass m = 746 g
diameter d = 10.4 cm
radius r = 5.2 cm
density of aluminum = 2.7 g/cm³
we know that
density × volume = mass
P × 4/3π( r₀³ - ri³) = m
so we substitute
2.7 × 4/3π( 5.2³ - ri³) = 746
11.3097( 5.2³ - ri³) = 746
( 5.2³ - ri³) = 746/11.3097
140.608 - ri³ = 65.961
ri³ = 140.608 - 65.961
ri³ = 74.647
ri = ∛74.647
ri = 4.21 cm
the sphere's inner radius is 4.21 cm so the Inner diameter is 8.42 cm
The inner diameter of the aluminum sphere is 8.42 cm.
The given parameters;
outer diameter of the sphere, d₀ = 10.4 cm mass of the sphere, m = 746 gdensity of aluminum, ρ = 2.7 g/cm³The volume of the aluminum sphere is calculated as follows;
[tex]volume = \frac{mass}{density} \\\\volume = \frac{746}{2.7} \\\\volume = 276.3 \ cm^3[/tex]
The volume of the sphere from the given outer and inner diameter is calculated as;
[tex]V = \frac{4}{3}\pi r^3\\\\V = \frac{4}{3}\pi \times \frac{d^3}{8} \\\\V = \frac{1}{6} \pi d^3\\\\V = \frac{1}{6} \pi (d_o^3 - d_i^3)\\\\d_o^3 - d_i^3 = \frac{6V}{\pi} \\\\d_i^3 = d_0^3 - \frac{6V}{\pi} \\\\d_i^3 = (10.4)^3 - \frac{6(276.3)}{\pi} \\\\d_i^3 = 597.23\\\\d_i = \sqrt[3]{597.23} \\\\d_i = 8.42 \ cm[/tex]
Thus, the inner diameter of the aluminum sphere is 8.42 cm.
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Suppose that a certain fortunate person has a net worth of $73.0 billion 7.30x10¹9). If her stock has a good year and gains $3.20 billion (3.20 x 109) in value, what is her new net worth? Express your answer to three significant figures.
Answer:
76.2 billion
Explanation:
73.0 + 3.20 billion = 76.2 billion
I really need help with this
Answer: i've done the same thing before kinda but anyway use this website that was recommended to me by a teacher https://www.britannica.com/science/mica (i got an A btw)
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
please mark me brainliest
HELP PLEASE I WILL MARK BRAINLIEST
Answer:
Acceleration.
Explanation:
Seems like u don't have time for a explanation. :
Answer:
A. Displacement
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