Answer:
It would not be safe to walk out to where waves are breaking due to the effect of rip currents
Explanation:
The water depth in the surf zone is between 5 to 10 meters deep and with a wavelength of 30 meters, the speed of the wave is considerably fast such that control for safety may be difficult
Also the speed of the wave is directly related to the depth of the water which means that where the wave described above is fast as well as the rip current, also the water depth is expected to be considerable for a non swimmer
It is best to seek for sign post regarding safe areas and do not go into the water where there are no lifeguards or marked safe zones.
It won't be safe to walk out to where the waves are breaking.
This is because the wavelength is 30 meters which is a characteristic of
areas with significant water depth in the range of 5-11 meters.Under these
conditions the waves are usually very fast and may get swept with the
current from the water waves when trying to run from it.
It is recommended that we stay in areas where the depth is noted as not
being much and should always seek help and clarity from the life guards so
as to prevent drowning and death.
Read more on https://brainly.com/question/17125479
Which may result from an increase in friction?
A: decreased traction
B: increased speed
C: reduced wear and tear
D: generation of heat
Answer:
Its Generation of Heat. or "D"Explanation:
Friction causes generation of heat and causes increased wear and tear.
The friction is a resistive force and is related to heat energy, so an increase in friction results in the generation of heat, so option D is correct.
What is friction?Two solid objects cannot roll or slide over one another due to the force of friction. Although frictional forces can be useful, such as the traction needed to walk without slipping, they can also present a large degree of resistance to motion. Automobile engines need about 20% of their power to overcome frictional forces in moving parts.
The fundamental source of friction between metals appears to be the adhesion forces between the contact zones of the surfaces, which are always microscopically uneven. Friction is produced by shearing, these "welded" seams, and the rubbing action of the rougher, tougher surface against the softer, smoother surface.
The friction is a resistive force trying to oppose the force applied As friction is related to heat when we increase the heat, the friction increases, and vice versa.
To know more about Friction:
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Two students are trying to measure how high a ball bounces when it is dropped from different heights. They dropped a ball from P and it bounced up till Q. They now have to record two measurements as shown below. Which measurements should they take?A.A B.B C.C D.D
Answer:
A.A
Explanation:
The balls usually bounce 60% of the original height because it stores 60% of the energy it had before the bounce. When a ball is dropped from a great height it has kinetic energy before it hits the ground which is the result of the bounce of ball. The size of ball does matter in this case, Large balls will bounce higher.
Signal propagation in the nervous system can be modeled as
a) A resistor network.
b) A wave of electricity that travels down conducting tissue.
c) A series of RC circuits.
Answer:
c) A series of RC circuits.
The region of magnetic influence around either pole of a magnet is called the magnetic field. The magnetic field line points out from the south magnetic pole and in from the north magnetic pole. This statement is:
Answer:
This statement is not true
Explanation:
Because The normal magnetic field line points out from the north magnetic pole and in from the south magnetic pole.
Answer:
false
Explanation:
hope this helps :)
The transfer of charge from clouds to the earth or cloud to cloud is called
That's called "lightning".
Answer:
The lightning itself is the transfer of charge from one region of a cloud to another or between the cloud and Earth. The narrow channel within which the flash of lightning occurs is heated suddenly to ~ 30,000 K, with essentially no time to expand.
Explanation:
Hope it helps
The density of water is 1000 kg m^3. What is the value expressed in gcm^-3 units? please help me..
(1) 1000 (2) 100 (3) 1 (4) 0.1 (5) 0.01
Here's the neat, cool way to convert units like this:
-- 1 kilogram = 1,000 grams
-- 1 meter = 100 centimeters
So . . . . .
(1000 kg/m³) x (1000 g/kg) x (1 m/100 cm)³ =
(1,000 kg/m³) x (1,000 g/kg) x (1 m³/1,000,000 cm³) =
(1,000 x 1,000 x 1 / 1,000,000) (kg-g-m³ / m³-kg-cm³) = 1 g/cm³
Which statement describes dynamic equilibrium? A. The forces on an object in motion are balanced. B. An object is accelerating due to forces acting on it. C. The forces on an object are unbalanced. D. The forces on a stationary object are balanced.
Answer: A. The forces on an object in motion are balanced.
Explanation:
The dynamic equilibrium is defined as the phase when an object moves at a constant velocity such that all forces on the object are balanced.
Simple case of dynamic equilibrium: A horizontal force is applied to an object making it run with a constant velocity across a surface.
Hence, the statement describes dynamic equilibrium is " The forces on an object in motion are balanced. "
So, the correct option is "A".
Answer:
Hope this helps!
find the molecular formula of the following
Answer: hello i am a hacker
Explanation:
magnesium sulphate=(24*1)+(32*1)+(16*4)=120 water=H2O=(1*2)+(1*16)=18 carbon dioxide=CO2=(12*1)+(16*2)=44 ammonia=NH3=(14*1)+(1*3)=17 alminiumsulphate=AL2(SO4)3=(26*2)+(32*3)+(12*16)=340 hydrogen peroxide=H2O2=(1*2)+(16*2)=34 zinc sulphate=ZNSO4=(65*1)+(32*1)+(16*4)=161
Two small, identical conducting spheres repel each other with a force of 0.035 N when they are 0.35 m apart. After a conducting wire is connected between the spheres and then removed, they repel each other with a force of 0.055 N. What is the original charge on each sphere? (Enter the magnitudes in C.)
Explanation:
Given:
distance between two sphere =0.35 m
Electrical repel force =0.035 N
Electrical repel force after connecting wire =0.055 N.
The electrical force between the two spheres:
[tex]F=k \frac{q_{1} q_{2}}{r^{2}}[/tex]
The electrical force between the two spheres after the wire is attached and removed:
[tex]F=k \frac{q^{2}}{r^{2}}[/tex]
[tex]q^{2}=\frac{F r^{2}}{k}[/tex]
[tex]q=r \sqrt{\frac{F}{k}}=0.35 \times \sqrt{\frac{0.055}{8.99 \times 10^{9}}}=6.46 \times 10^{-7} \mathrm{C}[/tex]
So the total charge of the two spheres [tex]=2 q=2 \times 6.46 \times 10^{-7}=1.29 \times 10^{-6} \mathrm{C}[/tex]
Then before connecting the wire, one sphere charge was [tex]q[tex] and the charge of the other sphere was [tex]\left(1.29 \times 10^{-6}-q\right)[/tex]
The electrical force between the two spheres before connecting the wire:
[tex]F=k \frac{q\left(1.29 \times 10^{-6}-q\right)}{r^{2}}[/tex]
[tex]q\left(1.29 \times 10^{-6}-q\right)=\frac{F r^{2}}{k}=\frac{0.035 \times(0.35)^{2}}{8.99 \times 10^{9}}=0.348 \times 10^{-12}[/tex]
[tex]-q^{2}+\left(1.29 \times 10^{-6}\right) q-\left(0.348 \times 10^{-12}\right)=0[/tex]
[tex]-q^{2}+\left(1.29 \times 10^{-6}\right) q-\left(0.348 \times 10^{-12}\right)=0[/tex]
How much work is done when 0.0042 C is moved through a potential difference of 12.0 V? Use W = qV A. 0.050 J B. 0.00035 J C. 2900 J D. 12 J
Answer:
Work done by charge (W) = 0.050 (Approx)
Explanation:
Given:
Charge (q) = 0.0042 C
Potential difference(V) = 12.0 V
Find:
Work done by charge
Computation:
Work done(W) = qV
Work done by charge (W) = (0.0042)(12)
Work done by charge (W) = 0.0504
Work done by charge (W) = 0.050 (Approx)
Answer:
Work done by charge (W) = 0.050 (Approx)
Explanation:
Charge (q) = 0.0042 C
Potential difference(V) = 12.0 V
Find:
Work done by charge
Computation:
Work done(W) = qV
Work done by charge (W) = (0.0042)(12)
Work done by charge (W) = 0.0504
Work done by charge (W) = 0.050 (Approx)
Squids propel themselves by expelling water. They do this by keeping water in a cavity and then suddenly contracting the cavity to force out the water through an opening. A 9 kg squid (including the water in the cavity) at rest suddenly sees a dangerous predator. If the squid expels 2 kg of water out of its body with a speed of 8 m/s, what would be its own escape speed
Answer:
v_squid = - 2,286 m / s
Explanation:
This exercise can be solved using conservation of the moment, the system is made up of the squid plus the water inside, therefore the force to expel the water is an internal force and the moment is conserved.
Initial moment. Before expelling the water
p₀ = 0
the squid is at rest
Final moment. After expelling the water
[tex]p_{f}[/tex] = M V_squid + m v_water
p₀ = p_{f}
0 = M V_squid + m v_water
c_squid = -m v_water / M
The mass of the squid without water is
M = 9 -2 = 7 kg
let's calculate
v_squid = 2 8/7
v_squid = - 2,286 m / s
The negative sign indicates that the squid is moving in the opposite direction of the water
Please help asap. A soccer player can kick a 0.370 kg football at 55 km/h. How much work does the soccer player have to do on the ball in order to give it that much kinetic energy?
Answer: 43.2 J
Explanation:
Work = change in KE
initial KE = 0
final KE = 1/2mv^2 = 1/2(0.370 kg)(15.2778 m/s)^2 = 43.2 J
i'm not sure about sig figs though
The following passage has not been edited. There is an error in each line. Write the
incorrect word and the correction in your answer sheet against the correct question
number. The first one has been done as an example. ( 1 x 4 = 4 )
Community service sensitize people to Error: sensitize ; Correction: sensitizes
other‟s needs and supports inclusive (a) Error: _______ ; Correction: ______
development to the underprivileged (b) Error: _______ ; Correction: ______
sections with society. Courses about social (c) Error: ______ ; Correction: _______
work prepares frontline workers to (d) Error: _______ ; Correction: ______
Answer:
(a) Error: Other's ; Correction: Others'
(b) Error: to ; Correction: for
(c) Error: with ; Correction: of
(d) Error: prepares ; Correction: prepare
Explanation:
a) The error is in the word "other's" as the position of apostrophe is wrong, so the correct word will be "others'", it shows plural nouns.
b) The error is in the word "to", so the correct word will be "for" as for is use to talk about a purpose.
c) The error is in the word "with" and the correct word will be "of" as of indicates relationships between other words including things that made of other things.
d) The error is in the word "preapres" and the correct word will be "prepare".
What is the wavelength of the following waves?
Answer:
i. the wavelength is 7.2 m
ii. the wavelength is 2.4 m
Explanation:
the wavelength of a wave is from crest to crest or from trough to trough.
One star has a temperature of 30,000 K and another star has a temperature of 6,000 K. Compared to the cooler star, how much more energy per second will the hotter star radiate from each square meter of its surface?
Answer:
The hotter star radiates 625 times more energy per second from each square meter of its surface
Explanation:
Temperature of the hotter star is 30000 K
temperature of the cooler star = 6000 K
From Stefan-Boltzmann radiation laws, for a non black body
P = εσA[tex]T^{4}[/tex]
where
P is the energy per second or power of radiation
ε is the emissivity of the body
σ is the Stefan-Boltzmann constant of proportionality
A is the area of the sun
T is the temperature of the sun
The sun can be approximated as a black body, and the equation reduces to
P = σA[tex]T^{4}[/tex]
For the hotter body,
P = σA([tex]30000^{4}[/tex]) = 8.1 x 10^17σA J/s
For the cooler body,
P = σA([tex]6000^{4}[/tex]) = 1.296 x 10^15σA J/s
comparing the two stars energy
==> (8.1 x 10^17)/(1.296 x 10^15) = 625
This means that the hotter star radiates 625 times more energy per second from each square meter of its surface
A mass of 1.15 kg of air at 111 kPa and 27 C is contained in a gas-tight, frictionless piston cylinder device. The air is now compressed to a final pressure of 0.84 MPa. During this process, heat is transferred from the air such that the temperature inside the cylinder remains constant. Calculate the work input (in kJ) during this process.
Answer:
Work input W = -200.39 KJ
Explanation:
From the question, we are given;
m = 1.15 kg
Constant temperature T1 = T2 = 27 + 273 = 300k
Since the temperature is constant, we can say that the process is isothermal
P1 = 111 KPa
P2 = 0.84 MPa = 0.84 * 1000 KPa = 840 KPa
Now what we want to calculate is W1-2
Mathematically, for isothermal process;
W1-2 = mRTlnP1/P2
where R can be obtained from table and it is equal to 0.287 KJ/kg.k
Hence;
W1-2 = (1.15)(0.287)(300)(ln 111/840)
W1-2 = 99.015 * -2.023871690525 = -200.39 KJ
Kindly note that the value of the work is negative because work is done on the system and not by the system
formula of minimmum pressure
Answer:
pressure=force/area
A disk-shaped merry-go-round of radius 3.03 mand mass 145 kg rotates freely with an angular speed of 0.681 rev/s . A 65.4 kg person running tangential to the rim of the merry-go-round at 3.41 m/s jumps onto its rim and holds on. Before jumping on the merry-go-round, the person was moving in the same direction as the merry-go-round's rim. What is the final angular speed of the merry-go-round?
Answer:
[tex]\omega_2=0.891\ rev/s[/tex]
Explanation:
Given that
Radius , r= 3.03 m
Mass of disk , M= 145 kg
Initial angular velocity
ω=0.681 rev/s
Mass of person , m= 65.4 kg
Velocity of person , V= 3.41 m/s
Initial mass moment of inertia
[tex]I_1= \dfrac{M\times R^2}{2}[/tex]
[tex]I_1= \dfrac{145\times 3.03^2}{2}=665.61\ kg.m^2[/tex]
Final mass moment of inertia
[tex]I_2= \dfrac{M\times R^2}{2}+m\times R^2[/tex]
[tex]I_2= \dfrac{145\times 3.03^2}{2}+65.4\times 3.03^2=1266.04\ kg.m^2[/tex]
[tex]Final\ angular\ velocity =\omega_2[/tex]
By using angular momentum equation
[tex]I_1\times \omega+m\times V\times R=I_2\times \omega_2[/tex]
[tex]665.61\times 0.681+65.4\times 3.41\times 3.03=1266.04\times \omega_2[/tex]
[tex]1129.01= 1266.04\times \omega_2[/tex]
[tex]\omega_2=\dfrac{1129.01}{1266.04}[/tex]
[tex]\omega_2=0.891\ rev/s[/tex]
Thus the angular velocity will be 0.891 rev/s
which discribes what a velocity/time graph would look like with no accelaration
help me helpppp the last words are experience a total
Answer:
False
Explanation:
Total internal reflection is a condition that occurs when light travels from dense medium to less dense medium.
From the table given in the question above,
Refractive Index of Whale oil = 1.460
Refractive Index of vacuum = 1
From the above, we can see that the whale oil has a higher Refractive Index than vacuum. This implies that the whale oil is denser than the vacuum.
Therefore, total internal reflection will occur when light travels from whale oil to vacuum because the whale oil is denser than the vacuum.
If y=5sin (3x -40)
Calculate the frequency and period
Answer:
0.477 Hz
2.09 s
Explanation:
y = A sin(ωx − φ)
A is the amplitude, ω is the angular frequency, and φ is the phase shift.
ω = 3 rad/s
f = ω / 2π ≈ 0.477 Hz
T = 1/f ≈ 2.09 s
A plane drops a package for delivery. The plane is flying horizontally at a speed of 120m/s,and the package travels 255 m horizontally during the drop. We can ignore air resistance.What is the package's vertical displacement during the drop?
Answer:
Package's vertical displacement(s) = 22.12 meter
Explanation:
Given:
Speed of plane = 120 m/s
Total distance = 255 m
Find:
Package's vertical displacement(s)
Computation:
Time taken = Distance / Speed
Time taken = Total distance / Speed of plane
Time taken = 255 / 120
Time taken = 2.125 s
Acceleration due to gravity(g) = 9.8 m/s²
Initial velocity (u) = 0
So,
Package's vertical displacement(s) = ut + (1/2)gt²
Package's vertical displacement(s) = (0)(2.125) + (1/2)(9.8)(2.125)²
Package's vertical displacement(s) = 22.12 meter
Answer: -22.1
Explanation:
I just did the Khan Academy and that was the answer, not the one provided by that one person. :)))
Ratan took a thin, solid piece of material. When he put it in water, it rose and floated. He took it out of the water and cut out holes in it as shown below. When Ratan puts the material with holes back in the water, what will happen?
Answer:
The material will still remain afloat.
Explanation:
The fact that the material floated on water as a solid piece means that the material is less dense than water. When a material is less dense than another liquid material, the material floats in the denser material. Cutting holes in the material will not reduce the buoyancy of the material. If the material had not floated as a single solid piece, then it will be said to be denser than the liquid material, and in such a case, if a strategic hole is cut on it to reduce its weight while maintaining its immediate volume, then it can be made to float. This is the principle behind metal floating ships.
A river flows with a speed of 3km/h in still water. A man who can swim with a speed of 5km/h wishes to reach a point on the other bank just opposite to the starting point. In which direction should he put his strokes and how long will he take to cross the river of width 1.2km? Please try to provide a diagram and step by step explanation.
Answer:
Explanation:
Let the angle required be θ with direction opposite to current .
cos θ = 3 / 5
θ = 53° .
Resultant velocity towards the opposite side
= √ ( 5 ² - 3²)
= 4 km /h
distance covered = 1.2 km
time taken = 1.2 / 4 = .3 h
= 18 min .
A 140-Hz sound travels through pure carbon dioxide. The wavelength of the sound is measured to be 1.92 m. What is the speed of sound in carbon dioxide?
Answer:
V = 268.8 m/s
Explanation:
The speed of a wave in general is given by the following formula:
V = fλ
where,
V = Speed of that wave
f = Frequency of the wave
λ = wavelength of the wave
In this case we have a sound wave, travelling across carbon dioxide. The properties of sound wave are as follows:
V = Speed of Sound in Carbon dioxide = ?
f = frequency of sound wave = 140 Hz
λ = wavelength of sound wave = 1.92 m
Therefore,
V = (140 Hz)(1.92 m)
V = 268.8 m/s
The specific latent heat of vaporisation of water is 2200 kJ kg, and the specific
heat capacity of water is 4200 J/ kg.K. A heating element is immersed in an
insulated cup of water. It takes five minutes to boil the water completely from an
initial temperature of 30°C. Assuming no heat is lost to the surroundings,
determine the mass of the water if the heating element is operating at 1000 W.
Answer:
0.12 kg
Explanation:
The amount of energy added is:
1000 W × (5 min × 60 s/min) = 300,000 J = 300 kJ
Heat to boil the water is:
q = mCΔT + mL
q = m (CΔT + L)
300 kJ = m (4.2 kJ/kg/K × (100°C − 30°C) + 2200 kJ/kg)
300 kJ = m (2494 kJ/kg)
m = 0.12 kg
pls help me with this question
Answer:
16 ms2 is the answer for this question
Experimenting with free fall, Mariana observes that her baseball takes 1.5 s to travel the last 30m before hitting the ground. From what height above the ground did Mariana drop the ball?
Answer:
37.8 m
Explanation:
At point 0, the ball is at height y₀.
At point 1, the ball is at height 30 m.
At point 2, the ball is at height 0 m.
Given:
y₁ = 30 m
y₂ = 0 m
v₀ = 0 m/s
a = -10 m/s²
t₂ − t₁ = 1.5 s
Find: y₀
Use constant acceleration equation.
y = y₀ + v₀ t + ½ at²
Evaluate at point 1.
y₁ = y₀ + v₀ t₁ + ½ at₁²
30 m = y₀ + (0 m/s) t₁ + ½ (-10 m/s²) t₁²
30 = y₀ − 5t₁²
Evaluate at point 2.
y₂ = y₀ + v₀ t₂ + ½ at₂²
0 m = y₀ + (0 m/s) t₂ + ½ (-10 m/s²) t₂²
0 = y₀ − 5t₂²
y₀ = 5t₂²
Substitute:
y₀ = 5 (1.5 + t₁)²
y₀ = 5 (2.25 + 3t₁ + t₁²)
y₀ = 11.25 + 15t₁ + 5t₁²
30 = 11.25 + 15t₁ + 5t₁² − 5t₁²
30 = 11.25 + 15t₁
t₁ = 1.25
30 = y₀ − 5t₁²
30 = y₀ − 5(1.25)²
y₀ ≈ 37.8
1. Chanice drives her scooter 7 kilometres north. She stops for lunch and then drives 5 kilometres east. What distance did she cover? What was her displacement?
Answer:
i. Distance covered is 12 kilometres.
ii. Her displacement is 8.6 kilometres.
Explanation:
Distance is a span of length between two points, while displacement is the distance moved in a specified direction. Distance is a scalar quantity, while displacement is a vector.
She drives 7 kilometres north, then 5 kilometres east later.
i. Distance covered = 5 + 7
= 12
Her distance covered is 12 kilometres.
ii. To determine her displacement, apply the Pythagoras rule to the sketch of her journey.
[tex]x^{2}[/tex] = [tex]5^{2}[/tex] + [tex]7^{2}[/tex]
= 25 + 49
= 74
x = [tex]\sqrt{74}[/tex]
= 8.6023
Thus, her displacement is 8.6 kilometres.
Which of the following object is in dynamic equilibrium?
Answer:
A car driving in a straight line 20 m/s
Explanation:
ayepecks silly