The boy on the bicycle is approaching the brick wall at a speed of 5.88 m/s. This is calculated using the formula for the Doppler effect which describes a frequency shift due to relative motion of the source and the observer.
Explanation:This problem deals with the Doppler effect, which is a shift in frequency perceived by an observer due to relative motion between the source of a wave (here, the bicycle horn) and the observer (the bicyclist hearing the reflected sound from the wall). In this case, we can use the formula for the Doppler effect when both the source and observer are moving towards each other:
f' = f (v + vo) / (v - vs)
where f' is the observed frequency (408 Hz), f is the source frequency (400 Hz), v is the speed of sound (340 m/s), vo is the observer's speed (the boy's speed) and vs is the source's speed (in this case, zero, since the wall is stationary).
Setting up the equation gives us:
[tex]408 = 400 (340 + vo) / (340 - 0).[/tex]boy, gives us vo = 5.88 m/s. Thus, the boy is riding his bicycle towards the wall at a speed of 5.88 m/s.
Learn more about Doppler effect here:https://brainly.com/question/28106478
#SPJ12
Using the Doppler effect principle, the speed of the boy on the bicycle relative to the air is approximately 6.8 m/s.
Explanation:The scenario given in the problem is a classic example of the Doppler Effect: the change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source. In this case, we have the frequency of the sound wave as observed in the stationary frame (400 Hz) and in the moving frame (the boy on the bicycle, 408 Hz). The speed of sound in air is given as 340 m/s.
The observed frequency f is related to the source frequency f0 and the speed of the observer v with respect to the medium (air in this case) by the formula: f = f0*(v + v0) / v, where v0 is the speed of the source of the wave.
Substituting the given values into the equation gives 408 Hz = 400 Hz * (340 m/s + v) / 340 m/s. Solving the equation yields the speed of the boy on the bicycle relative to the air, which comes out to be approximately 6.8 m/s.
Learn more about the Doppler Effect here:https://brainly.com/question/15318474
#SPJ11
A hair dryer draws 14.5 a when plugged into a 120-v line. assume direct current.
(a) What is its resistance? Express your answer to two significant figures and include the appropriate units."
(b) How much charge passes through it in 11 min ? Express your answer to two significant figures and include the appropriate units.
Solution
(a) We can calculate the resistance by using Ohm's law:
[tex]\Delta V= I R[/tex]
Since we know that [tex]\Delta V=120 V[/tex] and [tex]I=14.5 A[/tex], we can find R:
[tex]R= \frac{\Delta V}{I} = \frac{120 V}{14.5 A}=8.3 \Omega [/tex]
(b) The current is equal to the quantity of charge by unit of time:
[tex]I= \frac{Q}{t} [/tex]
In our problem, t=11min=660 s, so we can calculate the charge passed through the hair dryer:
[tex]Q=It=14.5 A \cdot 660 s = 9570 C[/tex]
Suppose that the resistance between the walls of a biological cell is 6.8 × 109 ω. (a) what is the current when the potential difference between the walls is 69 mv? (b) if the current is composed of na+ ions (q = +e), how many such ions flow in 0.86 s?
Final answer:
The current is 1.01 x 10^-11 A and 5.4 x 10^7 Na+ ions flow in 0.86 s.
Explanation:
In order to find the current, we can use Ohm's Law which states that current (I) is equal to the potential difference (V) divided by the resistance (R). So, the current can be calculated as:
I = V / R
Substituting the given values:
I = (69 mV) / (6.8 × 109 Ω)
I = 1.01 × 10-11 A
For part (b), we need to find the number of Na+ ions (q = +e) that flow in 0.86 s. We can use the equation:
q = I × t
Substituting the known values:
q = (1.01 × 10-11 A) × (0.86 s)
q = 8.7 × 10-12 C
Since 1 Na+ ion has a charge of +e, where e is the elementary charge (1.6 × 10-19 C), we can calculate the number of ions:
Number of ions = q / e = (8.7 × 10-12 C) / (1.6 × 10-19 C)
Number of ions = 5.4 × 107 Na+ ions
As the distance increases, the electrical forces of attraction between oppositely charged particles _____.
Answer:
Decreases
Explanation:
Coulomb found that the electric force between two point charges is inversely proportional to the square of the distance that separates them. Therefore, in this case, when the distance increases the repulsion force decreases and when the distance decreases the repulsion force increases.
An astronaut has a mass of 74.0 kg. 1) how much would the astronaut weigh on mars where surface gravity is 38.0% of that on earth? (express your answer to three significant figures.)
Which statement is true about the electromagnetic spectrum? The visible spectrum includes radio waves, light, and gamma rays. The colors you can see have the same wavelength. It has a range of visible and invisible forms of radiation. The waves travel at the speed of 2.998×105 meters/second.
Answer: It has a range of visible and invisible forms of radiation.
Explanation:
Electromagnetic wave is defined as the wave which is associated with both electrical and magnetic component associated with them. They can travel in vacuum as well and travel with the speed of light i.e [tex]2.998\times 10^8ms^{-1}[/tex]
The electromagnetic radiations consist of radio waves, microwaves, infrared ,Visible , ultraviolet, X rays and gamma rays arranged in order of increasing frequency and decreasing wavelengths.
Only visible light is visible to naked eyes.
The relationship between wavelength and frequency of the wave follows the equation:
[tex]\nu=\frac{c}{\lambda}[/tex]
where,
[tex]\nu[/tex] = frequency of the wave
c = speed of light
[tex]\lambda [/tex] = wavelength of the wave
From the above relation, it is visible that wavelength and frequency follow inverse relation. For increase in wavelength, the value of frequency decreases and vice-versa.
Assuming atmospheric pressure to be 1.01 x 10^5 Pa and the density of sea water to be 1025 kg/m^3, what is the absolute pressure at a depth of 15.0 m below the surface of the ocean?
The absolute pressure at a depth of 15.0m below the surface of the ocean is 150975 Pa.
Explanation:To calculate the absolute pressure at a depth of 15.0m below the surface of the ocean, we need to consider the pressure due to the weight of the water column above that point.
The pressure due to the weight of a fluid is given by the equation P = ρgh, where P is the pressure, ρ is the density of the fluid, g is the acceleration due to gravity, and h is the depth.
Substituting the given values, we have P = (1025 kg/m3) × (9.8 m/s2) × (15.0m) = 150975 Pa.
Therefore, the absolute pressure at a depth of 15.0m below the surface of the ocean is 150975 Pa.
What is the frequency of a clock waveform whose period is 750 microseconds?
Eddie the eagle, british olympic ski jumper, is attempting his most mediocre jump yet. after leaving the end of the ski ramp, he lands downhill at a point that is displaced 72.1 m horizontally from the edge of the ramp. his velocity just before landing is 33.0 m/s and points in a direction 30.0$^\circ$ below the horizontal. neglect any effects due to air resistance or lift. what was the magnitude of eddie's initial velocity as he left the ramp?
Eddie's initial velocity as he left the ramp is calculated as 28.61 m/s
Explanation:This physics problem involves two-dimensional motion or projectile motion. We can solve it by using the principles of conservation of energy and kinematics. The final horizontal velocity (vxf) can be calculated using the final velocity (v) and the angle (θ) below the horizontal through the formula vxf = v * cos(θ), which in this case gives us 33 * cos(30°) = 28.6 m/s. Since there's no horizontal acceleration involved in Eddie's jump, the initial horizontal velocity (vxi) equals the final horizontal velocity (vxf), hence vxi = 28.6 m/s.
Now, we can use the horizontal displacement (Δx) and vxi to calculate the total time of flight using the formula Δx = vxi * t, so the time of flight (t) = Δx / vxi = 72.1 m / 28.6 m/s = 2.52 s. Finally, using the time of flight, final vertical velocity (vyf), and the acceleration due to gravity (g), we can find the initial vertical velocity (vyi) using the formula vyf = vyi + g * t. Substituting the given values, we get - 33 * sin(30) = vyi - 9.8 * 2.52, which gives us vyi = -1.1 m/s.
As the last step, we find the magnitude of the initial velocity from the resultant of its vertical and horizontal components using the Pythagorean theorem: vi = sqrt[(vxi^2) + (vyi^2)], which comes out to be sqrt[(28.6^2) + (-1.1^2)] = 28.61 m/s.
Learn more about Initial Velocity here:https://brainly.com/question/35479651
#SPJ2
Give three ways you experience normal force throughout your day.
Answer: Static friction, sliding fiction, fluid fiction, and rolling friction
Explanation: static friction (friction that acts upon unmoving objects), sliding fiction (friction that occurs between two objects sliding past each other), fluid friction (is the force that resists motion when fluid is involved)and the last one is rolling friction (the force between a rolling object and a surface).
Suppose you have a 150-kg wooden crate resting on a wood floor. (a) what maximum force (in n) can you exert horizontally on the crate without moving it?
Final answer:
In physics, the maximum static frictional force equals the coefficient of static friction times the normal force. Once the crate starts slipping, the force of kinetic friction applies, and acceleration can be calculated using Newton's second law of motion.
Explanation:
The question involves concepts from Physics, specifically dealing with static friction and Newton's second law of motion. The maximum force that can be exerted on a wooden crate without moving it is equal to the maximum static frictional force. This force can be found by multiplying the coefficient of static friction (μ) between the wooden crate and the wood floor by the normal force, which, in this case, is equal to the gravitational force acting on the crate (mass × acceleration due to gravity, g).
If the static frictional force is overcome and the crate begins to slide, and assuming the applied force remains constant, we switch to dealing with kinetic friction. The magnitude of kinetic friction is usually lower than static friction. To find the acceleration of the crate once it starts moving, you would subtract the kinetic friction force from the applied force and then divide by the crate's mass, according to Newton's second law (F = ma).
For example, consider the question (a) What is the maximum force you can exert horizontally on a 120-kg wooden crate without moving it? The answer would be the product of the coefficient of static friction and the normal force, which equals the weight of the crate. If given (for example, μ=0.5), the calculation would be 588 N. For part (b), if the creates starts to slip, we then use Newton's second law to determine the magnitude of the crate's acceleration, which would be the net force divided by the crate's mass, resulting in an acceleration of 1.96 m/s².
In a biological reaction involving an enzyme, what does not directly participate in the reaction?
A.) The active site of an enzyme
B.) The active site of the substrate
C.) The inactive sure of the substrate
D.) The reactant chdcmicals
A small air plane's takeoff speed is 30 m/s. With constant acceleration it takes 150 m of runway to become airbourne. How long does it take to become airbourne?
A dog pulls on it's leash with a 10-N force to the left, but doesn't move. Identify the reaction force.
Maglev trains, like the one shown in the picture, use magnet fields to travel up to 600 miles per hour. Magnets on the bottom of the train and on the tops of the rails have similar magnetic poles. Based on properties of magnets, how do these magnets affect the train?
A)The two magnetic fields repel each other, causing the train to levitate, or hover, above the rails.
B)The powerful magnets greatly reduce the force of gravity, resulting in less friction and greater speed.
C)The train is able to stop immediately because the magnets on the rails attract the magnets on the train.
D)Maglev trains have extremely powerful magnets, greatly decreasing the force of gravity and allowing them to float.
Answer:
Its C
Explanation:
thank me later
Which of the following is a dark sticky substance that is found in tobacco?
a.
tar
b.
nicotine
c.
nitrogen
d.
carbon monoxide
A child bounces a 56 g superball on the sidewalk. the velocity change of the superball is from 20 m/s downward to 13 m/s upward. if the contact time with the sidewalk is 1 800 s, what is the magnitude of the average force exerted on the superball by the sidewalk? answer in units of n.
99 percent of the earth's atmosphere by mass is made up of only elements. These elements are
A)Carbon and oxygen
B)Nitrogen and oxygen
C)Hydrogen and oxygen
D) Helium and hydrogen
The correct answer is B) Nitrogen and oxygen
Explanation:
The atmosphere refers to the gaseous layer that covers a body such as a planet. The composition of the atmosphere varies according to the planet or body and therefore the elements found on it are different. In the case of our planet, the atmosphere is mainly composed of nitrogen and oxygen as these are 99% of the atmosphere, while other elements such as carbon dioxide represent the 1% missing. Also, the atmosphere is divided into different layers according to heigh this includes the troposphere, stratosphere, among others. Thus, 99 percent of the Earth's atmosphere is made up only of nitrogen and oxygen.
What is the purpose of the zigzag line on the periodic table
Answer : The purpose of the zigzag line on the periodic table is to separates the metal from the non-metal.
Explanation :
Metalloids : These are the elements that shows both the property of metals and non-metals.
For example : Boron, silicon, germanium, arsenic, antimony, tellurium, polonium and astatine are the metalloids.
Metalloids separates the metals from the non-metals.
The zigzag line on the periodic table represent the metalloids.
Non-metals are found to the right side of the zigzag line that gains electrons to attain stability.
Metals are found to the left side of the zigzag line that loses electrons to attain stability.
Hence, the purpose of the zigzag line on the periodic table is to separates the metal from the non-metal.
Alice and Marge are studying the properties of matter. The girls placed some an iron nail in a beaker containing water. Iron is a solid metal at room temperature. Iron is a shiny and malleable; it can be formed into shapes like the nails the girls used. Iron will turn reddish-brown in the presence of air or water as it rusts. Iron is a good conductor of electricity and heat. After 48 hours, the girls checked the nail in the water and compared it to the nail they left on the lab bench. Based on the girls' experiment, what is a chemical property of iron?
A) Iron is malleable. B) Iron rusts in water. C) Iron is a strong metal. D) Iron is a good conductor.
Answer: B) Iron rusts in water.
Explanation:
Physical property is defined as the property of a substance which becomes evident during physical changes. Example: Melting point , electrical conductivity, malleability,
Chemical property is defined as the property of a substance which becomes evident during chemical changes. Example: Reactivity with other substances
Rust is hydrated ferric oxide [tex](Fe_2O_3.xH_2O[/tex].
[tex]Fe\rightarrow Fe^{2+}+2e^-[/tex]
Corrosion of iron is called as rusting. Rust is hydrated ferric oxide [tex](Fe_2O_3.xH_2O[/tex].
[tex]Fe\righatarrow Fe^{2+}+2e^-[/tex]
[tex]O_2+4H^++4e^-\rightarrow 2H_2O[/tex]
[tex]4Fe^{2+}+O_2+4H_2O\rightarrow 2Fe_2O_3+8H^+[/tex]
Thus rusting of iron is a chemical property.
Answer: B) Iron rusts in water.
Water is to be pumped to the top of a building that is 366 m high. If the density of water is 1.00 x 10^3 kg/m^3, what amount of pressure is needed in the water line at the base of the building to raise the water to this height?
a.
1.26 x 10^6 Pa
b.
3.59 x 10^6 Pa
c.
5.39 x 10^6 Pa
d.
2.84 x 10^6 Pa
Which of the following is a useful tool in determining the genotype and phenotype of an organism?
Fossil Record
Punnett Square
Roots
Perfect Square
Which of the following is an accurate statement?
A. AC Generators produce current that is pulsating, but always remains positive.
B. Step-up voltage transformers have a lower number of turns in the primary than in the secondary winding.
C. DC Generators produce current with a voltage that changes from positive to negative.
D. Step-down voltage transformers have a different number of turns in the primary than in the secondary winding, so they change the incoming voltage to a higher voltage.
Suppose you had a parallel circuit with several identical light bulbs of equal resistance. if one bulb goes bad (or is disconnected), what happens to the brightness of the other bulbs?
In a parallel circuit, the brightness of the remaining bulbs isn't affected when one bulb goes bad or is disconnected. This is because each bulb has its own path to the voltage source, and neither the voltage nor the redistributed current through each bulb is affected by the removal of one bulb. Contrarily, in a series circuit, all bulbs would go dark.
Explanation:In a parallel circuit with several identical light bulbs of equal resistance, when one bulb goes bad or is disconnected, it doesn't affect the brightness of the other bulbs. This is because in a parallel circuit, each bulb has its own separate path to the voltage source. Therefore, the removal of one path (the bad or disconnected bulb) doesn't affect the potential difference or voltage across the other bulbs.
Let's take the two primary variables determining the brightness of a bulb - the voltage and current. In a parallel circuit, the voltage across each bulb remains the same, regardless of whether a bulb is removed or not. On the other hand, current, though different for each bulb depending on its resistance, isn't affected by the removal of one bulb because the total current just gets redistributed through the remaining paths, maintaining the original brightness of the other bulbs.
In contrast, if this were a series circuit, the scenario would be different. In a series circuit, the removal or failure of one bulb would disrupt the entire circuit (since there's only one path for the current to flow), causing all other bulbs to go dark.
Learn more about Parallel Circuit here:https://brainly.com/question/11409042
#SPJ3
What are the magnitude and direction of the force the pitcher exerts on the ball? (enter your magnitude to at least one decimal place.)?
(a) Through what distance does it move before its release? (m)
(b) What are the magnitude and direction of the force the pitcher exerts on the ball? (Enter your magnitude to at least one decimal place.)"
Solution
(a) The pitcher accelerates the baseball from rest to a final velocity of [tex]v_f = 16.5 m/s[/tex], so [tex]\Delta v=16.5 m/s[/tex], in a time interval of [tex]\Delta t = 181 ms=0.181 s[/tex]. The acceleration of the ball in the horizontal direction (x-axis) is therefore
[tex]a_x = \frac{\Delta v}{\Delta t}= \frac{16.5 m/s}{0.181 s}=91.2 m/s^2 [/tex]
And the distance covered by the ball during this time interval, before it is released, is:
[tex]S= \frac{1}{2} a_x (\Delta t)^2 = \frac{1}{2} (91.2 m/s^2)(0.181 s)^2=1.49 m [/tex]
(b) For this part we need to consider also the weight of the ball, which is [tex]W=mg=2.28 N[/tex]
From this, we find its mass: [tex]m= \frac{W}{g}= \frac{2.28 N}{9.81 m/s^2}=0.23 Kg [/tex]
Now we can calculate the magnitude of the force the pitcher exerts on the ball. On the x-axis, we have
[tex]F_x = m a_x = (0.23 kg)(91.2 m/s^2)=20.98 N[/tex]
We also know that the ball is moving straight horizontally. This means that the vertical component of the force exerted by the pitcher must counterbalance the weight of the ball (acting downward), in order to have a net force of zero along the y-axis, and so:
[tex]F_y=W=mg=2.28 N[/tex] (upward)
So, the magnitude of the force is
[tex]F= \sqrt{F_x^2+F_y^2}= \sqrt{(20.98N)^2+(2.28N)^2}=21.2 N [/tex]
To find the direction, we should find the angle of F with respect to the horizontal. This is given by
[tex]\tan \alpha = \frac{F_y}{F_x}= \frac{2.28 N}{20.98 N}=0.11 [/tex]
From which we find [tex]\alpha=6.2^{\circ}[/tex]
What is an intron?
A.) A part of DNA that codes for a functional protein
B.) A part of DNA that does not code for a functional protein
C.) The beginning part of the DNA molecule
D.) The end of part of the DNA molecule
If a ball is given an initial speed of 15 m/s on a horizontal, frictionless surface, how fast will the ball be rolling in 5 seconds?
Answer:
15 m/s
Explanation:
In a uranium fission reaction the uranium splits into 2 smaller atoms an energy. Where did the energy come from?
Isabel’s first car had a manual stick shift. After many years of driving an automatic car, she needs to use her sister’s car, which also has a stick shift. Isabel takes a few minutes to get used to shifting gears. Which memory system is she using to recall this information?
Final answer:
Isabel is using her implicit procedural memory, a form of long-term memory responsible for automatic skills, to recall how to use a manual stick shift after primarily driving an automatic car.
Explanation:
Isabel is utilizing her implicit procedural memory to recall how to shift gears in a stick shift car after having driven an automatic vehicle for many years. Procedural memory is a form of long-term memory that enables people to perform tasks without conscious awareness of the learned skills, such as riding a bike, typing on a keyboard, or driving. In this case, Isabel's ability to revert to using a manual stick shift despite the extended use of an automatic car illustrates the durability and automaticity of procedural memory.
Sound waves with large amplitudes push on the eardrum with more force and are heard as _______. Sound waves with small amplitudes push on the eardrum with less force and are heard as _______.
A certain aircraft has a liftoff speed of 127 km/h.
(a) What minimum constant acceleration does the aircraft require if it is to be airborne after a takeoff run of 277 m?
Final answer:
The minimum constant acceleration required for an aircraft to become airborne after a takeoff run of 277 meters is [tex]2.25 m/s^2[/tex] when converting the liftoff speed from km/h to m/s and applying the kinematic equation.
Explanation:
To determine the minimum constant acceleration required for an aircraft to become airborne after a takeoff run of 277 meters, we can use the kinematic equation:
[tex]$$ v^2 = u^2 + 2as $$[/tex]
Where:
v is the final velocity (liftoff speed), which needs to be converted from 127 km/h to m/s.
u is the initial velocity, which is 0 m/s since the aircraft starts from rest.
a is the acceleration, which we are trying to find.
s is the displacement, which is the distance of the takeoff run (277 m).
First, we convert the liftoff speed to m/s:
[tex]$$ 127 km/hr \times \frac{1000 m}{1 km} \times \frac{1 h}{3600 s} = 35.28 m/s $$[/tex]
Now we can use the kinematic equation to solve for a:
[tex]$$ 35.28^2 = 0^2 + 2a \times 277 $$ $$ a = \frac{35.28^2}{2 \times 277} = \frac{1244.6784}{554} = 2.2465 \frac{m}{s^2} $$[/tex]
The minimum constant acceleration required for the aircraft to be airborne is [tex]2.25 m/s^2[/tex] (rounded to two decimal places).