Answer:
a.) 20.4 h
b.) 3.46 km/h
Explanation:
Given that an English Channel is 35 km wide at its narrowest point, which is where most swimmers attempt to cross north to south from England to France. The current across this portion of the English Channel runs at about 2 km/h east to west.
a.) If a swimmer has a relative velocity to the shore of 3 km/h north to south, The resultant velocity (Vr) will be achieved by using Pythagoras theorem
Vr = [tex]\sqrt{2^{2} + 3^{2} }[/tex]
Vr = [tex]\sqrt{4 + 9}[/tex]
Vr = [tex]\sqrt{12}[/tex]
Vr = 3.46 m/s
To get how long it take her to cross the 35 km distance, Let us first find acceleration by using third equation of motion.
[tex]V^{2} = U^{2} + 2aS[/tex]
Where U = 0
Substitute all the parameters into the equation
[tex]3.46^{2} = 2 x a x 35[/tex]
11.97 = 70a
a = 11.97/70
a = 0.17 km/h^2
The time can be found by using equation
V = U + at
let U = 0
3.46 = 0.17t
t = 3.46/0.17
t = 20.35h
b. What must be her velocity relative to the water if she has a velocity of 3 km/h north to south relative to the shore?
her velocity relative to the water will be
Vr = [tex]\sqrt{2^{2} + 3^{2} }[/tex]
Vr = [tex]\sqrt{4 + 9}[/tex]
Vr = [tex]\sqrt{12}[/tex]
Vr = 3.46 m/s
Which choice correctly defines magnetic poles? the points on the end of magnet, where the magnetic field is strongest the point on a magnet where one magnetic field cancels out another magnetic field the middle of a magnet where the magnetic field is zero different ends of a magnet where the magnetic field is weakest
Answer:
A. The points on the end of magnet, where the magnetic field is strongest.
Explanation:
A magnet is a substance that has the ability to attract magnetic materials, e.g iron, steel etc. It comprises of two poles (north-N and south-S) each at its two ends. The N-pole and S-pole are the points on a magnet that have the strongest magnetic field. The magnetic fields originates from the north pole, and terminates in the south pole of a magnet.
When the poles of two different magnets are brought close together, attraction or repulsion may occur.
The option that defines the magnetic poles is the points on the end of the magnet, where the magnetic field is strongest.
What is a magnetic field?Attracting other iron-containing objects or aligning themselves in a magnetic field.
There are two poles of the magnet;
1. the North Pole.
2. the South Pole.
The same poles repel each other, while the opposite poles attract each other.
Thus, the correct option is A.
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PSYCHOLOGY QUESTION
Give a brief description of the factors involved in understanding the etiology of a disease
PLEASE NEED ANSWER ASAP
Answer:
Not sure what yours looking for but When a disease is widespread, epidemiological studies investigate what associated factors, such as location, swx, exposure to chemicals and many others, make a population more or less likely to have an illness, condition, or disease thus helping determine its etiology.
Answer:
Some anxiety disorders have different symptoms and it is important to figure out how those symptoms develop. Symptoms may develop from physiological, psychological, or environmental influences. Physiological factors may include heredity, chemical and hormonal imbalances, gender (females are more prone to anxiety than males), and anxiety sensitivity, which has to do with how one’s body reacts to chemical changes. Psychological influences focus on how one’s mind reacts to fearful situations. Environmental factors also influence how individuals deal with fearful situations. Environmental stress levels, how we think or interpret situations, and our observations of how others react to similar situations all impact how we manage anxiety.
Explanation:
In a container there are 2 liters of liquid, of which 75% is alcohol and the remaining 25% is water.
Determine how many cm3 of alcohol must be added to bring the alcohol percentage to 80%.
Answer:
There must be added 500 cm3 of alcohol to bring the concentration to 80%.
Explanation:
Concentration
The concentration of a solution is a measure of the amount of solute that has been dissolved in a given amount of solution.
In the container, there are 2 liters (2000 cubic centimeters) of a solution, 75% of which is alcohol (solute) and 25% of water (solvent).
The original amount of alcohol is:
H = 2000*75% = 1500 cc
The original amount of water is:
W = 2000*25% = 500 cc
When we add x cc of pure alcohol, there are 1500+x cc of alcohol out of 2000+x cc of solution.
The new concentration is calculated as:
[tex]\displaystyle \frac{1500+x}{2000+x}[/tex]
And it's known this concentration is 80% (0.8), thus:
[tex]\displaystyle \frac{1500+x}{2000+x}=0.8[/tex]
Multiplying by 2000+x:
[tex]1500+x = 0.8(2000+x)[/tex]
Operating:
[tex]1500+x = 1600+0.8x[/tex]
Rearranging:
[tex]x-0.8x=1600-1500[/tex]
[tex]0.2x=100[/tex]
[tex]x=100/0.2[/tex]
x= 500
There must be added 500 cm3 of alcohol to bring the concentration to 80%
An airplane starts from rest and accelerates at a constant 3.00 m/s2
for 20.0 s. What is its displacement in this time?
Answer:600 m
Explanation:
In sea-floor spreading, molten material rises from the mantle and erupts in the...
Answer:
along mid ocean ridges
Explanation:
In 1960, Harry Hess came up with the discovery that the floor of the oceans undergoes a movement. This movement is similar to that of being a conveyor belt. In this movement, continents are moved along with the oceans. The molten materials moves up to the mid-ocean ridge where it spreads and erupts. In this process the molten materials pushes the rocks sideways thereby emerging out from the mantel. The freezing of the molten material formed new rocks. This process is termed to be sea-floor spreading.
John walks four kilometers east, two kilometers north as shown in the diagram below. What is John’s displacement
4 km
11 km
2 km north
7 km east
How does the observed pitch of the buzzer change as it moves
observer?
pitch of the buzzer increased (higher tone) as it moves towards the observer
The pitch of the buzzer decreased (lower tone) as it moves towards the observer
The pitch of the buzzer stayed the same no matter where it was in relationship
to the observer
The answer is
Pitch of the buzzer increased (higher tone) as it moves towards the observer
The correct option that explains the change in the observed pitch of the buzzer as it moves towards the observer is;
A; pitch of the buzzer increased (higher tone) as it moves towards the observer
This is based on the concept of doppler effect which is defined as the change in frequency/pitch of a sound that is heard by an observer due to the fact that the sound source and the observer have different velocities with respect to the medium through the sound travels.Now, according to doppler effect, when the source of the sound moves towards the observer, the frequency will increase due to the fact that the time between successive sound waves is shortened. Thus, this means that the pitch will be higher. However, when the sound source moves away from the observer, the frequency would decrease due to the fact that the time between successive sound waves or the crest is now longer. Thus, the pitch will decrease.In conclusion, the pitch of the buzzer will increase as it moves towards the observer.
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characteristics of radiation from the sun's energy would be
A. heat from a distance source, elcetromagnatic waves and energy that travels through space.
B. Direct contact of the energy source of sufaces
C. Movement of heat through fluids
WHICH ONE IS THE ANSWER HELPPP
Answer:
Answer is A
Explanation:
Bathroom scales read the normal force that is exerted against the floor. What would a scale read when a 100 kg man is in an elevator accelerating upward at 1.2 m/s2? What would it read when the man is accelerated downward at 1.8 m/s2?
Answer:
a
When the lift is moving upward [tex]F = 1120 \ N[/tex]
b
When the lift is moving downward [tex]F = 820 \ N[/tex]
Explanation:
From the question we are told that
The mass of the man is [tex]m = 100 \ kg[/tex]
The upward acceleration is [tex]a_u = 1.2 \ m/s^ 2[/tex]
The downward acceleration is [tex]a_d = 1.80 \ m/s^2[/tex]
Generally the force which the scale will read when the man is moving downward is according to Newton second law represented as
[tex]F + mg = ma[/tex]
[tex]F = m (g - a_d)[/tex]
Here [tex]g = 10 m/s^2[/tex]
=> [tex]F = 100 (10 - 1.8)[/tex]
=> [tex]F = 820 \ N[/tex]
Generally the force which the scale will read when the man is moving upward is according to Newton second law represented as
[tex]F - mg = ma[/tex]
[tex]F = m (g + a_u)[/tex]
Here [tex]g = 10 m/s^2[/tex]
=> [tex]F = 100 (10 + 1.2)[/tex]
=> [tex]F = 1120 \ N[/tex]
Question 3 of 10
Why do electric charges that move through a magnetic field produce an
electric current?
A. The magnetic field exerts a force on only the negative charges in
the wire.
B. The magnetic field exerts a force on only the positive charges in
the wire.
C. The magnetic field pushes negative charges and positive charges
in the same direction.
D. The magnetic field pushes negative charges and positive charges
in opposite directions.
Answer: D
Explanation: a p e x :)
Answer:
B. The magnetic field pushes negative charges and positive charges in opposite directions.
What is the electric potential, i.e. the voltage, 0.30 m from a point charge of 6.4 x 10-C?
Answer:
V = 192 kV
Explanation:
Given that,
Charge, [tex]q=6.4\times 10^{-6}\ C[/tex]
Distance, r = 0.3 m
We need to find the electric potential at a distance of 0.3 m from a point charge. The formula for electric potential is given by :
[tex]V=\dfrac{kq}{r}\\\\V=\dfrac{9\times 10^9\times 6.4\times 10^{-6}}{0.3}\\\\V=192000\ V\\\\V=192\ kV[/tex]
So, the required electric potential is 192 kV.
Choose the best real world exzample of convection:
A. clouds forming in the atmosphere
B. touching a warm cooking pot handle
C. sitting in front of a warm fireplace
WHICH ONE IS THE ANSWER HELP PLESEEE
1. If all four switches below are turned on, which light bulb will light up? (W is wood, S is silver, and Yis yarn.)
A.Circuit A
B. Circuit B
C. Circuit C
D. Circuit D
The correct option is option (c).
The bulb in the circuit C will glow up.
Complete circuit:We know that for the light bulb to glow up, there must be finite current flowing in the circuit through the bulb.
But, for the current to flow in the circuit, first, the circuit must be complete.
As we can see in the figure provided in the question, circuit A is not complete, whereas circuit B, C, and D are complete. So from here we can reject the circuit A.
Now, the circuit B contains wood, circuit C contains silver and circuit D contains yarn. Only silver is an electrical conductor.
Therefore, circuit C is complete and current will flow through the bulb and it will glow up.
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How do pith balls become stationary?
A truck initially traveling at a speed of 22 m/s increases at a constant rate of 2.4 m/s^2 for 3.2s. What is the total distance travelled by the truck during this?
Answer:
82.7 m
Explanation:
u= 22m/s
a= 2.4 m/s^2.
t= 3.2 secs
Therefore the distance travelled can be calculated as follows
S= ut + 1/2at^2
= 22 × 3.2 + 1/2 × 2.4 × 3.2^2
= 70.4 + 1/2×24.58
= 70.4 + 12.29
= 82.7 m
Hence the distance travelled by the truck is 82.7 m
Use the term chemical change in a complete sentence
Answer:
A paper being burned is a chemical change.
A block is given an initial velocity of 8.0 m/s up a frictionless 28° inclined plane. (a) What is its velocity when it reaches the top of the plane? (b) How far horizontally does it land after it leaves the plane?
Answer:
A.) 8 m/s
B.) 7.0 m
Explanation:
Given that a block is given an initial velocity of 8.0 m/s up a frictionless 28° inclined plane.
(a) What is its velocity when it reaches the top of the plane?
Since the plane is frictionless, the final velocity V will be the same as 8 m/s
The velocity will be 8 m/s as it reaches the top of the plane.
(b) How far horizontally does it land after it leaves the plane?
For frictionless plane,
a = gsinø
Acceleration a = 9.8sin28
Acceleration a = 4.6 m/s^2
Using the third equation of motion
V^2 = U^2 - 2as
Substitute the a and the U into the equation. Where V = 0
0 = 8^2 - 2 × 4.6 × S
9.2S = 64
S = 64/9.2
S = 6.956 m
S = 7.0 m
What is vi for an object dropped from a raised position?
Answer:
Option C. vi = 0
Explanation:
An object held at a particular height above the ground is considered to be at rest. If the object is release from that height, the initial velocity (vi) is considered to be zero since the object is at rest or at a stand still position.
Thus,
Initial velocity (vi) = 0
5. Explain how forming an ionic bond makes metal and nonmetal atoms more stable.
6. Describe how metallic bonds contribute to the physical characteristics of a metal.
7. Describe the type of ions created through metallic bonding.
8. List the three types of atomic bonds and describe the types of atoms-metal
or nonmetal-that form each type of bond.
Speed and Motion you went from the starting line to the finish line at different rates. If you repeated the activity while carrying weights but keeping your times the same, how would your kinetic energy be affected?
Answer:
It will cause kinetic energy to increase.
Explanation:
Given that Speed and Motion you went from the starting line to the finish line at different rates.
If you repeated the activity while carrying weights but keeping your times the same, the weight carried will add up to the mass of the body.
And since Kinetic energy K.E = 1/2mv^2
Increase in the mass of the body will definitely make the kinetic energy of the body to increase.
Since the time is the same, that means the speed V is the same.
Weight W = mg
m = W/g
The new kinetic energy will be:
K.E = 1/2(M + m)v^2
This means that there will be increase in kinetic energy.
A balloon is filled with helium at sea level. The volume was measured to be 3.1 liters at a pressure of 0.97 atm. If the balloon is released, it drifts upward. At a height of 4 kilometers, the pressure is measured to be 0.61 atm. What is the new volume of the balloon?
5.0 L
0.19 L
4.9 L
1.9 L
Answer:
4.9L hope this helped!
Iron filings were sprinkled around these two magnets. What do the iron filings
show?
O A. They show that magnetic field lines point away from the north
pole of magnets.
B. They show the pattern made by the magnetic field lines around the
magnets
C. they show that magnetic field lines often cross over each other when magnets repel
D. they show the locations of the magnetic domains in the magnets
please help no ones questions match mine!!!
Answer:
B. They show the pattern made by the magnetic field lines around the
magnets
Explanation:
Using iron fillings, the pattern of the magnetic field lines around a bar magnet can be known.
Magnetic field lines are the line of force around a bar magnet.
These iron fillings will trace the pattern of the magnetic field around the magnet. The domains of the iron fillings begins to align and orient with that of the prevailing magnetic field around. Those areas with the strongest force will attract more fillings and those far away will attract lesser fillings.Answer:
B
Explanation: E Z
The speed of light in that material is slower or faster?
Cual es la fuerza de empuje que recibe un cuerpo de forma cilíndrica que mide 0.3 m de radio y 8m de altura, el cual se sumerge en alcohol si su densidad es de 790 Km/m3 tomando en cuenta la gravedad de 9.8m/seg2
Responder:
Fb = 17,5 kN
Explicación:
La expresión de la fuerza de empuje
Fb = ρgV ---------- 1
dónde
Fb = fuerza de flotación
ρ = densidad del fluido
g = aceleración debida a la gravedad
V = volumen de fluido
Paso uno:
datos dados
radio del cilindro = 0,3 m
altura h = 8m
densidad = 790 kg / m ^ 3
g = 9,8 m / s ^ 2
El volumen del cilindro se expresa como
V = πr ^ 2h
V = 3,142 * 0,3 ^ 2 * 8
V = 3,142 * 0,09 * 8
V = 2,26
El volumen es 2.26m ^ 3, el volumen del cilindro es igual al volumen de alcohol disparado
La expresión de la fuerza de empuje es
Fb = ρgV
sustituyendo tenemos
Fb = 790 * 9,8 * 2,26
Fb = 17514,26N
Fb = 17,5 kN
The amount of oxygen in the reactants is 4 atoms. In the products, the oxygen is distributed to water (H2O) and O2 gas. Which coefficients would be placed in front of water and oxygen?
2 in front of water and 2 in front of oxygen
1 in front of water and 2 in front of oxygen
1 in front of water and 1 in front of oxygen
2 in front of water and 1 in front of oxygen
Answer:
Answer:
2 in front of water and 1 in front of oxygen
Explanation:
This question is describing balancing a chemical reaction. A balanced chemical reaction has the same number of atoms of each elements on both the reactant and product side. According to the question, the reactants contains 4 atoms of oxygen. The reactants give rise to water (H20) and O2 in the products side.
This reaction is most likely the decomposition of hydrogen peroxide (H2O2) as follows:
H2O2 (l) ----> H2O (l) + O2(g)
Based on the description, H2O2 will be 2H2O2 as it is said to contain four atoms of oxygen. This means that, in order to have a balanced equation, we must place coefficient 2 in front of water and coefficient 1 in front of oxygen. That is;
2H2O2 (l) ----> 2H2O (l) + O2(g)
Explanation:
Answer:
2 in front of water and 1 in front of oxygen
Explanation:
i took the test and got 100 so it has to be right ;)
What happens to the strength of an electromagnet when the number of coils
in the solenoid is increased?
O A. It depends on what metal makes up the solenoid.
B. It increases.
C. It remains the same.
D. It decreases.
Answer:
It decreases
Explanation:
<3
When the number of coils in the solenoid is increased, the strength of the electromagnet also increases. So, the correct option is B.
What is meant by a solenoid ?A solenoid is defined as a type of electromagnet formed by winding a wire into a helical coil on a rod made of solid iron or steel.
Here,
The number of coils in the solenoid is increased. This increase in the number of coils, would affect the strength of the electromagnet.
The equation for the strength of the magnetic field of a solenoid can be written as,
B = μ₀NI/L
where,
B is the magnetic field strength
μ₀ is the permeability of free space
N is the number of turns of the coil
I is the current flowing through the solenoid
L is the length of the solenoid
From the equation, we can say that the magnetic field strength of a solenoid is directly proportional to the number of turns or the number of coils formed.
B [tex]\alpha[/tex] N
Therefore,
As, the number of coils in a solenoid increases, the magnetic field strength of the solenoid also increases.
Hence,
When the number of coils in the solenoid is increased, the strength of the electromagnet also increases.
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What is the difference between inertial mass and weight
Answer:
mass is the amount of matter in an object, whereas weight is the force exerted on an object by gravity
gravitational forces is ------ force
Answer:
Gravitational force is noncontact force
Explanation:
Contact force occurs due to the contact between two different objects. Non-contact force occurs due to either attraction or repulsion between two objects such that there is no contact between these objects. There is no field linked with the contact force. ... Gravitational force is an example of a non-contact force.
define frequency in terms of a wave
Answer:
Explanation:
For a wave, the speed is the distance traveled by a given point on the wave (such as a crest) in a given period of time. So while wave frequency refers to the number of cycles occurring per second, wave speed refers to the meters traveled per second
Two students are measuring the Gravitational Attraction between each other. One student weighs 120 kg. The other student weighs 108 kg. Calculate the gravitational pull they have on each other.
Answer:
[tex]F=8.64\times 10^{-9}\ N[/tex]
Explanation:
Given that,
Mass of student 1, m₁ = 120 kg
Mass of student 2, m₂ = 108 kg
Let they are at a distance of 10 m.
We need to find the gravitational pull they have on each other. The gravitational force acting between two objects is given by :
[tex]F=G\dfrac{m_1m_2}{r^2}\\\\F=6.67\times 10^{-11}\times \dfrac{120\times 108}{(10)^2}\\\\=8.64\times 10^{-9}\ N[/tex]
So, the gravitational pull between students is [tex]8.64\times 10^{-9}\ N[/tex].