Answer:
The pressure at the bottom of the river is less than that at the bottom of the lake.
Explanation:
From Bernoulli's equation, the pressure difference is given by
ΔP = ρgΔh + ρ(v₂² - v₁²)/2 where ρ = density of water, g = acceleration due to gravity, Δh = depth, v₁ = velocity at top, v₂ = velocity at bottom
For the lake, v₁ = v₂, since the velocity at the top and bottom are the same. So,
ΔP₁ = ρgΔh + ρ(v₁² - v₁²)/2 = ρgΔh + 0 = ρgΔh
P₂ - P₁ = ρgΔh
P₂ = P₁ + ρgΔh
For the river, v₁ < v₂, since the velocity at the top of the river is greater than at the bottom.
So,
ΔP₂ = ρgΔh + ρ(v₂² - v₁²)/2.
Since v₁ < v₂, ρ(v₂² - v₁²)/2 will be negative,
So,
ΔP₂ = ρgΔh - ρ(v₂² - v₁²)/2.
Since ρ(v₂² - v₁²)/2 is negative, making ΔP less than that in the lake.
So, ΔP₂ = ΔP₁ - ρ(v₂² - v₁²)/2.
ΔP₂ = P₃ - P₁
P₃ - P₁ = P₂ - P₁ - ρ(v₂² - v₁²)/2.
P₃ = P₂ - ρ(v₂² - v₁²)/2.
where P₃ = pressure at bottom of the river and P₂ = pressure at bottom of the lake and P₁ = atmospheric pressure at top of river and lake respectively.
Since the factor ρ(v₂² - v₁²)/2 is removed from the pressure at the bottom of the lake, the pressure at the bottom of the river is therefore less than that at the bottom of the lake.
Exercise combined with a _____________________________________can help control weight.
Answer:
healthy diet
Explanation:
Exercise and a healthy diet are the two things people do to stay healthy
Using examples, explain why the first and second Newton laws of motion are significant for living organisms.
Answer:
1) Newton's first law of motion states an object will remain at rest or in uniform will be in uniform motion in a straight line unless a force acts on it
2) Newton's second law states the acceleration of an object is directly proportional to the applied force acting on an object and inversely proportional to the mass of the object
Explanation:
1) With Newton's first law, we are able arrange things within a space and schedule meetings in time knowing that they will remain in place unless an external force changes their positions
2) An example of Newton's second law of motion is that small objects such as a ball are easily accelerated and can be given appreciable acceleration for flight by single, one time contact (such as kicking the ball) while larger objects such as a rock require sustained force application to change their location.
On the graph of voltage versus current, which line represents a 2.0 resistor?
Answer:
answer is B
Explanation:
Acc. to Ohm's Law:
V = I.R and therefore R=( V/I )
For line A, R = 6/2 = 3
line B, R = 4/2 = 2 ( for all the points plotted on this line the ratio of V and I is 2)
Line C = 2/2 = 1
Line D < 1
Hence, the correct answer is Line B :-)
Will mark as BRAINLIEST..... A balloon is ascending at the rate of 4.9 m/s. A packet is dropped from from the balloon when situated at a height of 100m. How long does it take the packet to reach the ground ? What is it's final velocity ?
Answer:
PFA
:-)
Explanation:
Which is NOT true of balanced forces?
A. Balanced forces will cause the motion of an object to
increase
B. Balanced forces are two equal forces pushing against
each other on an object,
C. Balanced forces do not cause a change in the motion of
an object
Which of the following would be the SI unit to use in measuring the temperature of hot liquid
Answer:
Kelvin
Explanation:
The SI unit to use in measuring the temperature of hot liquid is kelvin (K)
A train travels southwest from point A to point B through the Arizona desert at 55 mi/h. How far will the train travel six-and-a-half hours?
Answer:
357.5 miles
Explanation:
distance = speed × time
distance = (55 mi/h) × 6.5 h = 357.5 mi
The train will travel 357.5 miles in 6.5 hours.
I have this question where I think the answer is "directed north of east," but apparently it is not. Can someone explain: vectors v1 andv2 shown below have equal magnitudes. the vectors represent the velocities of an object at times t1, and t2, respectively. the average acceleration of the object between time t1 and t2 was...
Answer:
North of west
Explanation:
Acceleration is the change in velocity over change in time.
a = Δv / Δt
The x component of the acceleration is:
aₓ = (0 − v₁ₓ) / (t₂ − t₁)
aₓ = -v₁ₓ / (t₂ − t₁)
aₓ < 0
The y component of the acceleration is:
aᵧ = (v₂ − v₁ᵧ) / (t₂ − t₁)
aᵧ > 0
Therefore, the acceleration points northwest.
The average acceleration of the object between time t1 and t2 was directed north of west.
What is Vector?
A quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantity's magnitude.Here , the velocities are V1 and V2.V1 has two components , one in X direction Vx and other is in Y direction Vy.Now . acceleration = change in velocity with respect to time , i.e.a = v/t
Now, The x component of the acceleration is:
aₓ = (V2 − V1x) / (t2 − t1)
aₓ = -V1x/ (t2 − t1)
Because the x component of V2 is 0.
aₓ < 0
Similarly, The y component of the acceleration is:
aᵧ = (v₂ − v₁ᵧ) / (t₂ − t₁)
aᵧ > 0
Thus, The average acceleration of the object between time t1 and t2 was directed north of west.
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IMPORTANT 3 QUESTIONS!
Answer:
7. 20,000,000 mL.
8. 8,000 m.
9. 120,000 secs.
10. 4
Explanation:
7. Determination of the volume in millilitres (mL)
Volume in litre (L) = 20,000 L
Volume in millilitres (mL) =..?
The volume in mL can be obtained as follow:
1 L = 1,000 mL
Therefore,
20,000 L = 20,000 x 1,000 = 20,000,000 mL.
Therefore, 20,000 L is equivalent to 20,000,000 mL.
8. Determination of the distance in metre (m)
Distance in mile = 5 mile
Distance in metre =?
First, we shall convert from mile to kilometre.
This can be done as follow:
1 mile = 1.6 km
Therefore,
5 mile = 5 x 1.6 = 8 km
Finally, we shall convert 8 km to metre (m).
This is illustrated below:
1 km = 1,000 m
Therefore,
8 km = 8 x 1,000 = 8,000 m
Therefore, 5 miles is equivalent to 8,000 m.
9. Determination of the time in seconds.
Time = 400 minutes for 5 days.
First, we shall convert 400 mins to hour.
This is illustrated below:
60 minutes = 1 hour
Therefore,
400 mins = 400/60 = 20/3 hours
The time (hours) is 20/3 hours in 1 day.
Therefore, the time (hours) in 5 days will be = 20/3 x 5 = 100/3 hours.
Next, we shall convert 100/3 hours to minutes.
This is illustrated below:
1 hour = 60 minutes
Therefore,
100/3 hours = 100/3 x 60 = 2000 mins
Finally, we shall convert 2000 mins to seconds.
This is illustrated below:
1 mins = 60 secs
2000 mins = 2000 x 60 = 120,000 secs.
Therefore, the time is 120,000 secs.
10. Determination of the number of significant figures.
To obtain the significant figures of a number, we simply count all the numbers available.
Therefore, the number of significant figures for 9876 is 4.
Compare diffusion of chlorine gas into air and into vaccuum. Explain your answer
Answer:
Diffusion depends among many other things also upon the concentration gradient of the diffusing substance.For example if there are two boxes with given particles first isolated from each other and if they are bought in contact, then there is a net diffusion of particles from a box with higher concentration of particles to box with lower concentration. And also diffusion rate depends at any instant directly on the concentration difference between them at that instant.Now the vaccum is equivalent to an empty box which means with this one leads to a maximum diffusion rate when bought in contact with a box with particles because there is maximum concentration difference.That is vaccum is empty ( except for energy perturbations and a small concentration of particles which will be zero for our purpose) and any bunch of particles will find least resistance to diffuse as just outside this bunch there is ‘0' concentration of the particles.
A speed that will permit a train or other equipment to stop within one half the range of vision short of a train, engine, railroad car, man or equipment fouling a track, stop signal or a derail or switch lined improperly. When a train or engine is required to move at restricted speed, the crew must keep a lookout for a broken rail and not exceed 20 mph:__________
Answer:
This is called restricted speed
Terrestrial coordinates expanded into infinite space onto a celestial sphere is called the
A) ecliptic plane
B) galactic plane
C) equatorial coordinate system
D) terrestrial coordinate system
Answer:
The correct option is;
C) Equatorial coordinate system
Explanation:
The equatorial coordinate system is which has the most wide spread use in coordinate system for astronomy for mapping the location of celestial bodies such as stars by use of an imaginary projected celestial sphere or to rectangular coordinates with the Earth at the center. Extending the Earth's axis onto the celestial sphere is essentially the projection of the Earths axis outwards to intersect the sphere at the celestial poles.
c, 'equatorial coordinate system'
its the correct answer on the test,,, goodluckk :))!!
Name two safety measures commonly used in electric circuits and
appliances
Answer:
Here are two security mechanisms that are widely used in electrical circuits as well as appliances.
Explanation:
Electric Fuse: A sequence, an electrical fuse remains attached which preserves the connection from overburdening as well as avoids short-circuiting. Proper apparatus throughout all electrical circuits whereby any existing leakage in such an electrical system is passed to the surface while individuals who use the equipment are not getting the shock.we hammer the broader side of a nail and not its sharp end to put it in wood .why ?
Explanation:
We hammer the broader side of a nail instead of its sharp end to put it in wood. It is a concept based on the pressure exerted.
The force acting per unit area of an object is called pressure exerted. It means that pressure is inversely proportional to the area of cross section i.e. area increases, pressure decreases and vice versa.
The broader side of a nail has more area as compared to the sharp end. It means that the broader side will exert less pressure on them which make it easier for us to fix it into the wood.
A bat is flitting about in a cave, navigating via ultrasonic bleeps. Assume that the sound emission frequency of the bat is 38.9 kHz. During one fast swoop directly toward a flat wall surface, the bat is moving at 0.015 times the speed of sound in air. What frequency does the bat hear reflected off the wall?
Answer:
40085 Hz
Explanation:
We are given; Sound frequency emmision of bat;f = 38.9 kHz = 38900 Hz
Bat is moving at 0.015 times the speed of sound in air.
Speed of sound in air = 343 m/s
The formula for waves reflected off the wall is calculated from Doppler equation as:
f' = f(v + v_d)/(v - v_s)
Where;
f is the frequency = 38900 Hz
f' is the detected frequency,
v_d is the velocity of the detector = 0.015 × 343 = 5.145
v_s is the velocity of the source = 0.015 × 343 = 5.145 m/s
v is the velocity of the sound = 343 m/s
Thus;
f' = 38900(343 + 5.145)/(343 - 5.145)
f' ≈ 40085 Hz
i) A 100 W and 60 W bulb are joined in series and connected to the mains. Which bulb
will glow brighter? Why?
ii) A 100 W and a 60 W bulb are joined in parallel to the mains. Which bulb will
glow brighter? Why?
Answer:
i) 60 W
ii) 100 W
Explanation:
In each case, the bulb that dissipates the most power is the bulb that glows brighter. Power is voltage times current (P = VI). Using Ohm's law, we can rewrite this as P = I²R or P = V²/R.
Bulbs are rated at a certain power for a certain voltage. P = V²/R, so the bulb with the lower resistance will have the higher power rating. Therefore, the 100 W bulb has a lower resistance than the 60 W bulb.
i) They are in series, so they have the same current. P = I²R, so the bulb with the higher resistance will glow brighter. That's the 60 W bulb.
ii) They are in parallel, so they have the same voltage. P = V²/R, so the bulb with the lower resistance will glow brighter. That's the 100 W bulb.
Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She wants to increase her time what should she do
Answer:
C. Walk four times per week
Explanation:
If she wants to increase her time then, she has to walk four times per week.
What is speed?The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is a meter/second. The generally considered unit for speed is a meter per second.
The mathematical expression for speed is given by
speed = total distance /Total time
As given in the problem Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She must walk four times a week if she wants to extend her time.
Thus, the correct answer is option C.
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The question is incomplete, the complete question is,
Lyla walks three times per week for 45 minutes at a speed of 4.0 miles per hour. She wants to increase her time. What should she do?
A. Walk at 4.5 miles per hour.
B. Walk for 50 minutes.
C. Walk four times per week.
D. Walk up and down more hills.
The speed of light in space is 3.00 x 10^8 m/s. The time for light from the sun to reach earth is 8mins and 20 seconds. Therefore, the distance from the Sun to Earth is
Select one:
A. 2.40 x 10^9 m
B. 8.64 x 10^12 m
C. 1.50 x 10^11
D. 2.25 x 10^9
Answer:
C. 1.50×10¹¹ m
Explanation:
First, convert the time to seconds.
8 min × (60 s/min) + 20 s = 500 s
Distance = speed × time
d = (3×10⁸ m/s) (500 s)
d = 1.50×10¹¹ m
The distance from the Sun to the Earth is 1.50 × 10¹¹. Speed is the distance travelled by an object in a particular time period. Thus, the correct option is C.
What is the Speed of light?
The speed of light in vacuum is commonly denoted by c. It is a universal physical constant. The speed of light (c) is exactly equal to 3.00 x 10⁸m/s (meter per second).
The speed of an object is the rate of change of position with respect to time. It is also defined as the distance covered by an object with respect to time. It can be calculated by dividing the distance travelled by an object by the time taken. It is a scalar quantity as it has only magnitude and no direction.
Speed = Distance / time
Distance = Speed × Time
Distance = 3.00 × 10⁸ × 500
Distance = 1500 × 10⁸
Distance = 1.50 × 10¹¹
Therefore, the correct option is C.
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A copper-nickel alloy of composition 50 wt% Ni-50 wt% Cu is slowly heated from a temperature of 1200°C (2190 °F). (a) At what temperature does the first liquid phase form? (b) What is the composition of this liquid phase? (c) At what temperature does complete melting of the alloy occur? (d) What is the composition of the last solid remaining prior to complete melting?
Answer:
HELLO BELOW IS THE ATTACHED DIAGRAM USED TO ANSWER YOUR QUESTION AS IT WAS MISSING
A) 1270⁰c
B) 65%
C) 1320⁰c
D) 62%
Explanation:
Nickel alloy composition : 50 wt% Ni - 50 wt%
initial temperature = 1200⁰c = 2190⁰F
A) The temperature at which the first liquid phase form
from the attached diagram the temperature at which the first liquid if formed is 1270⁰c ( at point 2 )
B ) The composition of this liquid phase ( THE FIRST LIQUID )
the composition is found at point 3
wt % of Nickel = 35%, wt% of copper = 100 - 35 = 65%
C ) The temperature at which the alloy melts completely
from the attached diagram the temperature = 1320⁰c ( point 4 )
D) The composition of the last solid remaining prior to complete melting
this can be gotten at point 5 and calculated as
wt % of Ni = 62%
wt % of Cu = 100 - 62 = 38%
A particular celestial body orbits at a particular speed. For every two orbits it makes, another celestial body orbits three times. This orbital resonance would correspond to which musical interval?
Answer:
Explanation:
frequency of first body f₁ = 2 / T where T is time taken by it for making two orbits
frequency of second body f₂ = 3 / T
ration of two frequency
f₁ / f₂ = 2 / 3
This ratio is called perfect fifth in musical interval .
A rifle bullet with mass 8.00 g and initial horizontal velocity 280 m/s strikes and embeds itself in a block with mass 0.992 kg that rests on a frictionless surface and is attached to one end of an ideal spring. The other end of the spring is attached to the wall. The impact compresses the spring a maximum distance of 15.0 cm. After the impact, the block moves in SHM. Calculate the period of this motion.
Answer:
0.4113772 s
Explanation:
Given the following :
Mass of bullet (m1) = 8g = 0.008kg
Initial horizontal Velocity (u1) = 280m/s
Mass of block (m2) = 0.992kg
Maxumum distance (x) = 15cm = 0.15m
Recall;
Period (T) = 2π√(m/k)
According to the law of conservation of momentum : (inelastic Collison)
m1 * u1 = (m1 + m2) * v
Where v is the final Velocity of the colliding bodies
0.008 * 280 = (0.008 + 0.992) * v
2.24 = 1 * v
v = 2.24m/s
K. E = P. E
K. E = 0.5mv^2
P.E = 0.5kx^2
0.5(0.992 + 0.008)*2.24^2 = 0.5*k*(0.15)^2
0.5*1*5.0176 = 0.5*k*0.0225
2.5088 = 0.01125k
k = 2.5088 / 0.01125
k = 223.00444 N/m
Therefore,
Period (T) = 2π√(m/k)
T = 2π√(0.992+0.008) / 233.0444
T = 2π√0.0042910
T = 2π * 0.0655059
T = 0.4113772 s
The period of the simple harmonic motion (SHM) is 0.42 s.
The given parameters;
mass of the bullet, m₁ = 8 g = 0.008 kginitial horizontal velocity of the bullet, u = 280 m/smass of the block, m₂ = 0.992 kginitial velocity of block, u₂ = 0extension of the spring, x = 15 cm = 0.15 mThe final velocity of the system after the impact is calculated as follows;
[tex]m_1 u_1 + m_2u_2 = v(m_1 + m_2)\\\\0.008(280) \ + \ 0.992(0) = v(0.008 \ + \ 0.992)\\\\2.24 = v(1) \\\\v = 2.24 \ m/s[/tex]
The spring constant is calculated as follows;
[tex]\frac{1}{2} kx^2 = \frac{1}{2} mv^2\\\\k = \frac{mv^2}{x^2} \\\\k = \frac{(0.008 + 0.992))\times 2.24^2}{(0.15)^2} \\\\k = 223 \ N/m[/tex]
The angular speed of the simple harmonic motion (SHM) is calculated as follows;
[tex]\omega = \sqrt{\frac{k}{m} } \\\\\omega = \sqrt{\frac{223}{(0.008 + 0.992)} }\\\\\omega = 14.933 \ rad/s[/tex]
The period of the oscillation is calculated as follows;
[tex]T = \frac{2\pi }{\omega} \\\\T = \frac{2\pi }{14.933} \\\\T = 0.42 \ s[/tex]
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Based on its location on the periodic table, which element would be most likely to form a negative ion? A. Bromine (Br) B. Strontium (Sr) C. Potassium (K) D. Magnesium (Mg)
your answer is...
C. potassium
solve 1 for x if a=-9.8, v=2.7, and t= 35
Answer:
6097 = x
Explanation:
x = VT + at²/2
x= 2.7 * 35 + 9.8 * (35)²/2
x=6097
select the correct relationship of the densities of the given substances: !●water < iron < aluminium < mercury ● Iron < water < mercury < aluminium ● water < aluminium < iron < mercury ● none of the above. asap plz!!!
Answer:
option a is correct
Explanation:
water ∠iron∠aluminium∠mercury
water density =1.0000
iron =7.487
aluminium=2.07
mercury=13.59
What is the observation and what is the inference in the following text. Explain.
The chimpanzee climbed the tall tree. The chimpanzee must be very strong,
Observation: The chimpanzee climbed the tall tree.
Inference: The chimpanzee must be very strong,
Explanation:
An inference differs from an observation because an inference is a guess or possible explanation about a phenomenon. On the other hand, an observation is a statement based on evidence gathered through the senses. In this context, the sentence that is an observation is "The chimpanzee climbed the tall tree" because this statement is based on visual evidence. Moreover, the inference is "The chimpanzee must be very strong" because this is just a guess to explain how the chimpanzee climbed up the tree.
Need help finding the average speed.
Explanation:
To find the average of these numbers, we just have to add the three numbers together and divide by 3.
2.07 + 0. 74 + 1.33 = 4.14. 4.14 / 3 = 1.381.09 + 1.40 + 0.31 = 2.8. 2.8 / 3 ≈ 9.3333333/ 9 1/30.95 + 1.61 + 0.56 = 3.12 / 3 = 1.040.81 + 1.89 + 1.08 = 3.78 / 3 = 1.26Suppose an experiment is designed to test the durability of batteries in different conditions. All of the batteries tested are double-A (AA) Brand X. All sets of batteries are preconditioned in different environmental conditions for exactly 168 hours (1 week).
Set 1: 0°C (freezing point of water)
Set 2: 24°C (approximately room temperature)
Set 3: 37°C (approximately body temperature)
The batteries are then continuously used to power identical mechanical drummer toys. As long as the toy keeps drumming the battery is considered functional. The drumming time for each toy is measured as an indication of battery durability. In this experiment, which condition is not controlled?
A.) temperature
B.) brand of batteries
C.) test for durability
D.) type of battery (battery size)
Answer:
I assume its c. Since its talking about testing.
Explanation:
Answer:
The answer is test of durability
Explanation:
given that the amplitude of the scattered light is (1) directly proportional to that of incident light (2) directly propotional to the volume of the scattering dust particles (3)inversely proportional to its distance from the scattering particles and (4) dependent upon the wavelength of the light. show that the intensity of scattered light varies as 1/wavelength^4
Answer:
The correct answers are 2, 4
Explanation:
The dispersion of light occurs due to the interaction of electromagnetic radiation with matter, let's analyze the phenomenon, when a ray of light reaches a particle is absorbed and subsequently re-emitted in all directions, for radiation of lower wavelength (higher frequency ) the highest absorptions and therefore the missionary also the highest; An example of this is the blue light from the atmosphere, which is the absorption of blue light and its subsequent re-emission
Based on this explanation, the dispersion in gas particles or molecules is proportional to the frequency of the light (inversely proportional to the wavelength) and is also proportional to the number of dispersing particles in the air, that is, to the total volume of the particles. dispersers.
The correct answers are 2 and 4
Select the correct answer. x y 2.5 6.25 9.4 88.36 15.6 243.63 19.5 380.25 25.8 665.64 The table lists the values for two parameters, x and y, of an experiment. What is the approximate value of y for x = 4? A. 11 B. 16 C. 24 D. 43
Answer: B. 16
Explanation:
The given table:
x y
2.5 6.25
9.4 88.36
15.6 243.63
19.5 380.25
25.8 665.64
Here, we observed that value of y is the square value of x.
i.e. [tex]y=x^2[/tex] [For example 2.5²=6.25, 9.4²=88.36, 15.6²=243.63]
Put x=4, we get
[tex]y=4^2=16[/tex]
Hence, the approximate value of y for x = 4 is 16.
So, the correct option is B. 16 .
Answer:
The answer is A.
Explanation:
Which of the following is a true statement about mass and weight? Mass is a measure of how much matter an object has, while weight is a measure of how much space the object takes up. Mass will not change based on location, while weight will change based on gravitational pull. Mass is a measure of a gravitational pull on an object, while weight is a measure of how much matter is an object has. Mass is proportional to the force of gravity, while weight is proportional to the amount of mass.
Answer:
Mass will not change based on location, while weight will change based on gravitational pull.
Explanation:
The formula for weight is mass*gravitational pull, hence weight changes based on gravitational pull
Mass will not change based on location, while weight will change based on gravitational pull. This is a true statement about mass and weight.
What are mass and weight?The most fundamental characteristic of matter is mass, which is one of the fundamental quantities in physics. Mass is a term used to describe how much matter is there in a body. The kilograms is the SI unit of mass (kg). A body's mass remains constant at all times.
The amount of weight t indicates how much gravity is pulling on a body. The weight formula is provided by: w = mg
Weight being a force The SI unit of weight is the Newton, which is also the same as the SI unit of force (N). When we look at how weight is expressed, we can see that it depends on both mass and the acceleration caused by gravity; while the mass may not change from one location to another, the acceleration caused by gravity does.
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