Answer:
The teacher should swim in a direction 29.24° North of East
Explanation:
Given that the there is a water current across the lake, and the physics teacher intends to swim directly across the lake, the direction the physics teacher will have to swim is found as follows;
The speed of the water current is given by the speed of the floating leaf traveling with the water current
Distance traveled by the leaf = 4.2 m South
Time of travel of the leaf = 5.0 s
Speed of leaf = 4.2/5 = 0.84 m/s = Speed of the water current
Swimming peed of the teacher, v = 1.9 m/s
To swim directly across the lake, the teacher has to swim slightly in the opposite direction of the water current, the y-component of the teacher's swimming speed should be equal to and opposite that of the speed of the water current.
Y-component of v = v×sin(θ), where θ is the angle of the direction, the teacher should swim
Therefore;
1.9 × sin(θ) = 0.84
sin(θ) = 0.84/1.9 = 0.44
θ = 26.24°
That is the teacher should swim in a direction 29.24° North of East.
To cross the lake the teacher has to swim in a direction 29.24° North of the East
Finding the direction of speed required:
The speed of the water current can be derived from the speed of the floating leaf :
The distance traveled by the leaf L = 4.2 m South
Time taken T = 5s
So, the speed of the leaf is:
u = 4.2/5
u = 0.84 m/s South
So, the speed of the current is 0.84 m/s South
Now, it is given that the speed of the teacher is, v = 1.9 m/s East
To cross the lake the speed of the teacher must be in a Northeast direction so that the North component of the speed of the teacher cancels out the speed of the current which is directed towards the South.
Let, the speed of the teacher makes an angle of θ from the EAST.
So, the North component is given by:
v(north) = vsinθ
it must be equal to the speed of the current:
vsinθ = u
1.9 × sinθ = 0.84
sinθ = 0.84/1.9
sinθ = 0.44
θ = 26.24°
The teacher should swim in a direction 29.24° North of East.
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Una masa de 0,5 kg está sobre una pendiente inclinada 20º sujeta mediante una cuerda paralela a la pendiente que impide que deslice. Si no hay rozamiento, ¿qué fuerza hace la cuerda?
Answer:
4.61 N
Explanation:
masa = 0.5 kg
ángulo de inclinación = 20°
Peso normal de la masa = mg
donde m = masa
g = aceleración debido a la gravedad = 9.81 m/s^2
Peso normal = 0.5 x 9.81 = 4.905 N
Si la masa se mantiene en su lugar mediante una cuerda paralela al plano, y no hay fricción en la masa, entonces
La fuerza sobre la cuerda = peso normal x cos ∅
donde ∅ = 20 °
La fuerza sobre la cuerda = 4.905 x cos 20°
==> 4.61 N
Two charged objects are separated by some distance. The charge on the first object is greater than the charge on the second object. How do the forces that the two objects exert on each other compare
Even though the charge on the first object is greater, the forces that the two objects exert on each other are equal
The solubility of barium nitrate is 9.02 g/100 g H2O at 20°C. A 15.2 g sample of barium nitrate is added to 200.0 g of water at 20°C. Is the solution saturated, unsaturated, or supersaturated?
Answer:
The solution is unsaturated.
Explanation:
Saturated solutions are those solutions with the maximum amount of solute completely dissolved by the solvent. This indicates that although more solute is added, it does not dissolve. In this case the amount of solute is equal to the solubility coefficient.
The supersaturated solution is one in which the amount of solute exceeds the solubility of the solvent, that is, it has a greater amount of dissolved solute than that which it admits at that temperature. In this case a solution contains solute above the solubility coefficient.
A solution is considered to be unsaturated if the mass of dissolved solute is less than that corresponding to that of saturation. This indicates that it is possible to add more solute and that it dissolves. In this case the solution contains solute below the solubility coefficient.
The solubility of barium nitrate is 9.02 g/100 g H₂O at 20°C.
A 15.2 g sample of barium nitrate is added to 200.0 g of water at 20°C. This is: 15.2 g /200 g H₂O. Dividing by two you get: 7.6 g /100 g H₂O
Comparing with the solubility of barium nitrate, you can see that the mass of dissolved solute is less than the corresponding one. This indicates that the solution is unsaturated.
a physical quantity Z is given by z=ad/g .calculte the relatibe error in z
Answer:
e_{r} = Δa /a + Δd /Δ d + Δg / g
Explanation:
The error or uncertainty of a quantity is given by several factors, the most direct error is the absolute one that is given by the appreciation of the instruments, when some quantities obtained by a mathematical formula we must know how each error is programmed in the total error, we can see this with the relative error
the calculated quantity is Z
its relative error is
[tex]e_{r}[/tex] = ΔZ/Z = 1/Z (dZ /da Δa + dZ /dd Δd + dZ /dg Δg)
e_{r} = 1 / Z (d /g Δa + a /g Δd + ad !1/g²! Δg)
e_{r} = Δa /a + Δd /Δ d + Δg / g
notice that we take the worst case.
The measured quantities have absolute errors Da, Dd, Dg
1. A note has a wavelength of 0.77955 m. If the speed of sound is 343.00 m/s, what pitch is this note? 2. A note has a wavelength of 0.52028 m. If the speed of sound is 343.00 m/s, what pitch is this note? please no funny answers
Answer:
1.) 440 Hz
2.) 659.3 Hz
Explanation:
1.) Given parameters are:
wavelength = 0.77955 m.
speed of sound = 343.00 m/s
Frequency = speed/ wavelength
Substitute speed and wavelength into the formula
Frequency = 343/ 0.77955
Frequency = 439.99
Frequency = 440 Hz approximately
2.) The parameters given are:
wavelength = 0.52028 m.
speed of sound = 343.00 m/s
Using the same formula
Frequency = speed/wavelength
Substitute all the parameters into the formula
Frequency = 343 / 0.52028
Frequency = 659.3 Hz approximately
The pitch of a note depends on the frequency of the sound waves.
The pitch of a sound increases as the frequency of the sound waves increases.
Answer:
1.) 440 Hz
2.) 659.3 Hz
Explanation:
1.) Given parameters are:
wavelength = 0.77955 m.
speed of sound = 343.00 m/s
Frequency = speed/ wavelength
Substitute speed and wavelength into the formula
Frequency = 343/ 0.77955
Frequency = 439.99
Frequency = 440 Hz approximately
2.) The parameters given are:
wavelength = 0.52028 m.
speed of sound = 343.00 m/s
Using the same formula
Frequency = speed/wavelength
Substitute all the parameters into the formula
Frequency = 343 / 0.52028
Frequency = 659.3 Hz approximately
The pitch of a note depends on the frequency of the sound waves.
The pitch of a sound increases as the frequency of the sound waves increases.
Calculating heat gained, need help!!!
Q=(m)(c)(triangle T)
trial 1:
Q=(0.4)(4.186 J/kg)(78)=?
trial 2:
Q=(0.6)(4.186 J/kg)(78)=?
trial 3:
Q=(0.45)(4.186 J/kg)(75)=?
Explanation:
q = mCΔT
where m is mass,
C is specific heat capacity,
and ΔT is change in temperature.
Make sure all your units match. Assuming the substance is water, C = 4186 J/kg/°C.
Trial 1:
q = (0.4 kg) (4186 J/kg/°C) (78°C)
q = 130,600 J
Trial 2:
q = (0.6 kg) (4186 J/kg/°C) (78°C)
q = 195,900 J
Trial 3:
q = (0.45 kg) (4186 J/kg/°C) (75°C)
q = 141,300 J
Fig.4.1
The switch S is closed for a period of 5.0 minutes. Calculate
(a)
the current through each resistor.
чре
(b)
the current through the battery.
rad
rad
(c)
the total charge which passes through the battery.
ma
(d)
the energy supplied by the battery.
ars
Answer:
A
Explanation:
The speed of electromagnetic waves in a vacuum __________. The speed of electromagnetic waves in a vacuum __________. is larger for longer wavelengths is the same for all waves regardless of wavelength is the same as the speed of sound is larger for higher energies
Answer:
is the same for all waves regardless of wavelength
Explanation:
Electromagnetic waves are often collectively called light. Light has become a generic name that is applied to all electromagnetic waves. The arrangement of electromagnetic waves according to their respective wavelengths is called the electromagnetic spectrum.
When passing through a vacuum, all electromagnetic waves irrespective of their individual wavelengths must possess the same speed. This is called the speed of light in a vacuum. The speed of light in a given medium is a constant and applies to all electromagnetic waves irrespective of their frequency and wavelength.
If you are asked to modify the robots or drones that are currently used , what kind of modifications you would do and suggest any two fields where it can be used.
Explanation:
In recent times of pandemic, robots can be use as replacement of labor in the industries. Mundane tasks can be programmed in their system so that they can used readily.
Drones can used delivery for essential goods and services, so that human interference can be least and the spread of virus can be curbed.
In a recent example, Argentina where aerial data has reportedly been used to accelerate the construction of emergency hospitals.
You are playing a violin, where the fundamental frequency of one of the strings is 440 Hz, as you are standing in front of the opening of a long tube that is closed at the other end. As you play, you notice that the first time you hear an echo from the tube is when the sound from the 440 Hz string is in its fourth harmonic. Assuming you are playing this string on earth, what must be the length of the tube? What is the next higher harmonic number for the same string on the violin when you hear the next higher harmonic echo from the tube?
Answer:
a) L = 440 cm
Explanation:
In the open tube on one side and cowbell on the other, we have a maximum in the open part and a node in the closed part, therefore the resonance frequencies are
λ₁ = 4L fundamental
λ₃ = 4L / 3 third harmonic
λ₅ = 4L / 5 five harmonic
The violin string is a fixed cure in its two extracts, so both are nodes, their length from resonance wave are
λ₁ = 2L fundamental
λ₂ = 2L / 2 second harmonic
λ₃ = 2L / 3 third harmonic
λ₄= 2L / 4 fourth harmonic
They indicate that resonance occurs in the fourth harmonic, let's look for the frequency
v =λ f
for the fundamental
v = λ₀ f₀
V = 2L f₀
for the fourth harmonica
v = λ₄ f ’
v = L / 2 f'
2L f₀ = L / 2 f ’
f ’= 4 f₀
f ’= 4 440
f ’= 1760 Hz
for this frequency it has the resonance with the tube
f ’= 4L
L = f ’/ 4
L = 1760/4
L = 440 cm
b) let's find the frequency of the next harmonic in the tube
λ₃ = 4L / 3
λ₃ = 4 400/3
λ₃ = 586.6 cm
v = λf
f = v / λlam₃
f₃3 = 340 / 586.6
f3 = 0.579
as the minimum frequency on the violin is 440 Beam there is no way to reach this value, therefore there are no higher resonances
Unpolarized light is incident onto three polarizers with their transmission axes oriented in such a way that the first and the last make a 39 angle between them, and the middle one makes the same angle with the first and the last one. Find the percentage of the incident light which passes through these three polarizers.
Answer:
I₃ = I₀ 0.395
Explanation:
Polarized light passing through a polarizer must comply with Malus's law
I = I₀ cos² θ
Before starting, let's analyze the angle between the polarizers, the second has the same angle with the first and the third, so it is at the midpoint
θ₂ = 39/2 = 19.5
now let's analyze the light that passes through each polarizer, as the incident is unpolarized through the first polarizer half the intensity comes out
I₁ = I₀ / 2
the second polarizer comes out
I₂ = I₁ cos² 19.5
I₂ = I₀ / 2 cos² 19.5
through the third polarized the intensity passes
I₃ = I₂ cos² 19.5
I₃ = (I₀ /2 cos² 19.5) cos² 19.5
I₃ = I₀ 0.395
The fan on a personal computer draws 0.3 ft3/s ofair at 14.7 psia and 708F through the box containing the CPU and other components. Air leaves at 14.7 psia and 838F.Calculate the electrical power, in kW, dissipatedby the PCcomponents
Answer:
0.12 kW
Explanation:
Given that
The flow rate of air (V)=0.3 ft³/s
V=0.008 m³/s
Pressure, P=14.7 psia
P=1.013529 atm=101.325 kPa
Inlet temperature = 70° F=294.261 K
Exit temperature = 83° F=301.483 K
We know that , specific heat capacity of the air
Cp=1.005 kJ/kg.K
The mass flow rate of air is given as
[tex]\dot{m}=\dfrac{P\times V}{R\times T}\\\dot{m}=\dfrac{101.325\times 0.008}{0.287\times 294.261}\\\dot{m}= 0.0095\ kg/s[/tex]
By using energy conservation
[tex]Electric\ power =\dot{m}\times C_p\times (T_2-T_1)\\Electric\ power =0.0095\times 1.005\times (83-70)=0.12\ kW[/tex]
Therefore electric power dissipate by components will be 0.12 kW.
SOMEONE HELP ME PLEASE!!!
a. What is the displacement of the car in the graph?
b. What distance has the car travelled?
Answer:
a. 2 m
b. 4 m
Explanation:
a. Assuming d is the position of the car, the displacement is the difference between the final position and the initial position. 3 m - 1 m = 2 m.
b. From t = 0 to t = 2.5, the car moves a distance of 3 m. From t = 2.5 to t = 4, the car moves another 1 m.
So the car moves a total distance of 4 m.
Someone help me?
Isaac throws an apple straight up in the positive direction) from 15 m above the ground, reaching a
maximum height of 38 meters. Neglecting air resistance, what is the ball's velocity when it hits the
ground?
Answer:
-27.3 m/s
Explanation:
Given:
y₀ = 38 m
y = 0 m
v₀ = 0 m/s
a = -9.8 m/s²
Find: v
v² = v₀² + 2a (y − y₀)
v² = (0 m/s)² + 2 (-9.8 m/s²) (0 m − 38 m)
v = -27.3 m/s
Or, you can solve with energy.
PE = KE
mgh = ½ mv²
v² = 2gh
v = -27.3 m/s
Write difference between upstroke and downstroke of water pump
Explanation:
Upstroke is a mechanism which helps to raise the plunger and downstroke helps to help lower the plunger. On the up-stroke of the plunger, the lower valve opens and the upper valve is closed. ... Whereas, on the downstroke, the lower valve closes and the upper one opens.
A man has a mass of 110kg. What is his weight?
His weight depends on where he is, because
Weight = (mass) x (gravity in the place where the mass is) .
For example:
-- If this man is on Mars, his weight is (110 kg) x (3.7 m/s²) = 408 Newtons
-- If he is on the Moon, his weight is (110 kg) x (1.6 m/s²) = 176 Newtons
-- If he is on Earth, his weight is (110 kg) x (9.8 m/s²) = 1,078 Newtons
-- If he is in a spacecraft coasting from one to another, his weight is zero.
Average velocity is different than average speed because calculating average velocity involves a)Distance b)Time c)Motion d)Displacemnet
Answer:
D. Displacement
Explanation:
got it right on edge
Average velocity is different than average speed because calculating average velocity involves Displacement, therefore the correct option is option D.
What is Velocity?The total displacement covered by any object per unit of time is known as velocity. It depends on the magnitude as well as the direction of the moving object. It can also be represented by the infinitesimal rate of change of displacement with respect to time. The unit of velocity is meter/second.
The mathematical expression for velocity is given by
velocity= displacement / time taken
In the displacement time graph the slope of the curve represent the velocity of the object ,the rate of change of velocity is known as the acceleration of the object .
In the velocity time graph the slope of the curve represent the acceleration of the body, The unit of acceleration is metre per second Square
The total distance traveled by an object is different than the total displacement covered by it because the displacement is a vector quantity and it is calculated on the basis of the shortest distance traveled by the body or object.
The main difference between the distance and the displacement is that displacement can be positive or negative or zero but distance can never be negative.
Let’s understand understand with example of average velocity ,suppose an object is moving with 200 m displacement covered in a time of 15 seconds then the average velocity of the object is 13.33 m/s.
Thus, average velocity is different than average speed because calculating average velocity involves Displacement, therefore the correct option is option D.
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explain schodingers cat with example
Answer:
Explanation:
In Schrodinger's imaginary experiment, you place a cat in a box with a tiny bit of radioactive substance. When the radioactive substance decays, it triggers a Geiger counter which causes a poison or explosion to be released that kills the cat. ... The cat ends up both dead and alive at the same time.
Answer:
Explanation:
was simply a teaching tool schrodinger used to illustrate how some people misinterpreting quantum theory, in quantum theory particles can exist in a superposition of states at the same time and collapse down to a single state upon interaction with other particles
Ionizing radiation is radiation of sufficient energy to produce charged atoms. All of these describe ionizing radiation. is radiation of sufficient energy to produce ions. is radiation of sufficient energy to remove electrons from atoms.
Answer:
Is radiation of sufficient energy to produce ions.
Is radiation of sufficient energy to remove electrons from atoms.
Explanation:
Ionization radiation is a radiation that travels at a high speed, and possesses sufficient speed to knock electrons off of an atom or a molecule, ionizing the atom. Ionization radiation can be made of travelling subatomic particles, or an electromagnetic wave with high energy, usually the types found at the end of the electromagnetic spectrum. Some subatomic particles that produce ionization are alpha particle, beta particles, and neutron. The electromagnetic waves with ionization abilities includes Gamma rays. -rays, and high energy ultraviolet rays.
plssss answer it i am stuck in between..prove that pascal is a derived unit using the formulae...
Answer:
See below
Explanation:
We know that the unit of pressure is Pascal.
We have,
Pressure = [tex] \frac{force}{area} [/tex]
[tex] = \frac{m \times g}{l \times b} [/tex]
[tex] = \frac{kg \: \times \: {meter \: per \: second \: }^{2} }{ {m}^{2} } [/tex]
[tex] = kg \: {m}^{ - 1} \: {s}^{ - 2} [/tex]
The unit of pressure i.e Pascal is derived unit because it is expressed depending on more than two units i.e kg / [ m × s × s ]
Hope this helps..
best regards!!
in a cricket match there are 5000 spectators counted 10 by 10 the number of significant figure in the measurement will be
Answer:
[tex]\boxed{3 \ Significant \ figures}[/tex]
Explanation:
Total spectators = 5000
Counted by the groups of ten, So at last the result will be:
=> 5000/10 = 500
Significant figures in 500 are 3
A sports car moving at constant velocity travels 120m in 5.0s. If it then brakes and comes to a stop in 4.0s,what is the magnitude of it's acceleration?
✔ First calculating the speed :
V = d(in m)/t(in s)
V = 120/5 V = 24 m/s✔ You now know the average car's speed, is time it takes to stop it completely, so you can calculate its acceleration :
a = V/t
a = -24/4 a = 6 m/s² The car has an acceleration of 6 m/s².Which image below represents the electric field lines between two positively charged particles? (2 points)
A positive particle sits in the center of a dotted circle. There is a negative particle along the dotted circle.
Two particles sit side by side. There are curved field lines that point from one particle to the other in a counter clockwise direction above the particles and a clockwise direction below the particles.
Two particles sit side by side. There are curved field lines that point away from each particle. The particle on the right has field lines pointing to the right. The particle on the left has field lines pointing to the left.
One particle sits in the center of curved field lines that extend beyond the particle then return to the particle. Arrows along the curved field lines point in a clockwise direction above the particle and a counter clockwise direction below the particle.
The electric field is defined as the aura of electrons in which it exerts force and attracts the negetivily charged particles.
The electric field line depends on the following:-
The magnitude of the electrons.The correct option is as C.
The flow of the electric field line is from Positive to negative and it always attracts the negative particle. The alike particles attract each other while the like particles are repealed each other.
Hence the correct option is C that is two particles sitting side by side. There are curved field lines that point away from each particle. The particle on the right has field lines pointing to the right. The particle on the left has field lines pointing to the left.
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Give reasons.
a) Sunlight does not fall on the ground where cloud forms shadow.
Answer:
Sunlight passing through a cloud is scattered in various directions. Some photons eventually find their way out the bottom of the cloud, some are reflected upwards, and some are absorbed, serving to warm the cloud. Since only a fraction of the light makes it to ground level, you have a shadow.
Explanation:
Hope it helps you
Bumper car A (281 kg) moving +2.82 m/s makes an elastic collision with bumper car B (209 kg) moving +1.72 m/s. What is the velocity of car B after the collision?
The velocity of car B after the calculation can be obtained as 5.5 m/s.
What is a collision?We have to look at the principle of the conservation of the linear momentum and that is what we need so as to be able to deal with the problem that we have in this question as we have it here.
We know that the total momentum of the system would have to be constant and the implication of this is that the momentum before collision must be the same as the momentum after collision if we have been able to designate the system as a closed system.
Using the formula as we have shown it, we know that;
Momentum before Collison must be equal to momentum after collision
As such we have the following as shown below;
(281 * 2.82) + (209 * 1.72) = (281 * 0) + (209 * v)
792.42 + 359.48 = 209 v
v = 5.5 m/s
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A 70.0 kg skier is at rest at the top of a 120m hill. Assuming friction is negligible.
A) What is the speed of the skiers at the bottom of the hill?
Answer:
49 m/s
Explanation:
Initial potential energy = final kinetic energy
PE = KE
mgh = ½ mv²
v = √(2gh)
v = √(2 × 10 m/s² × 120 m)
v = 49 m/s
Do you think, are we need to learn Measurement in Physics. Explain how the measurement is necessary and inevitable in real life situations?
Answer:
Measurement is inevitable because in every single thing we do we measure.for instance, if you are a family of four,the food prepared will be less than the food prepared for a family of about 15 people.this is measurement.if not so,the food prepared will go waste.again, the drugs prescribed by the doctor is measured to avoid over dose or under dose of medication.this can be harmful to ones health
7. An astronaut weighs 900N on earth. On the moon, he weighs 150N. Calculate the
moons' gravitational strengh
Answer:
Moons’ gravitational strength = weight of astronaut on the moon / mass of astronaut.
= 150 / 90 = 1.67 Nkg-1
Explanation:
Which of the following is a device that uses an inclined plane?
Check all that apply.
A. knife
B. wheelchair ramp
C. bicycle
D. half-pipe at a skate park
Answer:
A and B
Explanation:
Answer:
B. wheelchair ramp
D. half-pipe at a skate park
Hope that helps!
A series combination of 12 Ω and 3 Ω is connected in parallel with another series combination of 6 Ω and 3 Ω. If a potential difference of 4 V is applied across it find the i) current drawn from the battery ii) current through 12 Ω resistor (iii)potential difference across 6 Ω resistor?
Answer:
Explanation:
Resultant of 12 and 3 ohm in series = 15 ohm
Resultant of 6 and 3 ohm = 9 ohm
Total resultant resistance of circuit = 15 x 9 / (15 + 9)
= 5.625 ohm
current drawn from battery = 4 / 5.625
= .711 A
ii )current through 12 ohm = 4 / (12 + 3 ) , because potential diff over 12 and 6 ohm will be 4 V .
current through 12 ohm = .267 A
iii )
current through 6 ohm
= .711 - .267
= .444 A
potential difference
= .444 x 6
= 2.664 V .