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
what is the role of the communicator in a dc generator?
A) it keeps the electric current flowing in one direction
B) it keeps the magnetic fields of the permanent magnet steady
C) it causes the magnetic fields of the permanent magnets to reverse
D) it causes the electric current to constantly reverse its direction
Answer:
C
Explanation:
Answer:
A)
Explanation:
it keeps the electric current flowing in one direction
What two factors determine how much potential energy an object has?
Answer:
The mass of the object and its height in the gravitational field of the Earth.
Explanation:
If we are talking about gravitational potential energy which is defined as:
[tex]U=m\,*\,g\,*\,h[/tex]
being "m" the object's mass, "g" the acceleration due to gravity, and "h" the height at which the object is located relative to the conventionally picked level for zero of potential energy.
As long as the value of "g" is constant, the only two variables that determine the gravitational potential energy are the mass (m) of the object and its relative height (h).
Answer:
The objects weight and height above Earth's surface
Explanation:
K12 :)
A bird flying 5.0 m overhead sees me drop it, and starts to dive straight down towards the bread the instant I release it. She catches it after it falls 3.0 m. Assuming she accelerates constantly from rest (0 = 0) at the time I let go of the bread, what is her acceleration?
Answer:
15
Explanation:
muntiply the 5.0.3.0 ,you will get ans
A ball is launched from the ground with the horizontal speed of 30 m/s and vertical speed of 30 m/s what angle was the ball launch at?
Answer:
45 degrees
Explanation:
angle of launch=arctan(vertical velocity/ horizontal velocity)
angle = arctan(30/30) = 45 degrees
What is a potential psychological outcome of regulary playing sports
This question is incomplete because the options are missing; I found the complete question:
What is a potential psychological outcome of regularly playing sports? Select one of the options below as your answer:
a. restlessness
b. improved mood
c. depression
d. lack of energy
The answer to this question is B. Improved mood
Explanation:
Practicing a sport regularly has multiple positive effects including physical and psychological benefits. In the case of psychological effects, this includes an improved mood, this is because practicing a sport reduces stress significantly and it is often associated with positive emotions such as motivation, confidence, or pride. Moreover, interacting with others in group sports allow individuals to positively interact with others, which contributes to a better mood. Thus, one potential psychological outcome of playing sports is an improved mood.
with solutions please give with solution
if u give me with solution I will mark in brainlist
Answer:
Magnitude of Force : 0.8 N
Explanation:
We know that the velocity of this particle changes from 15ms⁻¹, or in other words 15m / s, to the respective velocity 25m / s over the course of 2.5 seconds. Given this information we can determine the acceleration of the particle,
a = v₁ - v₂ / t = 25 - 15 / 2.5 = 10 / 2.5 = 4m / s²
Knowing the acceleration we can calculate the magnitude of the force using the formula f = ma - Newton's second law of motion,
f = m [tex]*[/tex] a = 200g [tex]*[/tex] 4m / s² = 800 g [tex]*[/tex] m / s²
Remember however that Newtons are in the standard units kg [tex]*[/tex] m / s². Therefore we have to convert 800 g to kg to receive our solution,
800 g = 800 / 1000 kg = 0.8 kg,
Magnitude of Force = 0.8 N ; Solution = Option B
The period of a pendulum is the time it takes the pendulum to swing back and forth once. If the only dimensional quantities that the period depends on are the acceleration of gravity, g, and the length of the pendulum, ℓ, what combination of g and ℓ must the period be proportional to? (Acceleration has SI units of m • s-2.)
Answer: √(L/g)
Explanation:
Here we only work with the units:
The unit of the period is units of time, so we have:
[T] = [s]
Now, the units of the length of the pendulum are units of distance:
[L] = [m]
And the units of the acceleration are:
[g] = [m/s^2]
Now, we want to work with those two in such way that the end result is only in seconds.
First, we can see that in g we have seconds square, so we know that we should use a square root.
Then we can divide L by g in order to remove the distance unit, and to have the time unit in the numerator
[L/g] = [m*s^2/m] = [s^2]
Now we apply the square root:
[√(L/g)] = [√s^2] = [s]
Then the combination is: √(L/g)
T = k*√(L/g)
where k is the constant of proportionality.
A group of Advanced Open Water Divers plans to make two dives. The first dive is on a reef in 90 feet of water for 20 minutes. The group then remains on the surface for 1 hour. The second dive is on a wreck in 60 feet of water, with a planned bottom time of 30 minutes. What will be the ending pressure group after the second dive
Answer:
The ending pressure is R.
Explanation:
This is Recreational scuba diving (R). According to standards, this diving has prescribed depth limit of 130 ft. This means that the limit must include a depth that is not greater than 130 ft while using only compressed air and not even requiring a decompression stop.
Now, from the question, we can see that that there was a prescribed limit of 60ft of water with a planned bottom time of 30 minutes.
Thus, the ending pressure is R.
A body of mass 20 kh changes its velocity from 5m/s to 17 m/s in 3 seconds. find the force applied on this body .
please answer fast
Answer:
80 N.
Explanation:
The following data were obtained from the question:
Mass (m) = 20 Kg
Initial velocity (u) = 5 m/s
Final velocity (v) = 17 m/s
Time (t) = 3 secs
Force (F) =.?
Next, we shall determine the acceleration of the body.
Acceleration is simply defined as the rate of change of velocity with time. Mathematically, it is expressed as:
Acceleration = change of velocity /time
Acceleration (a) = (final velocity (v) – initial velocity (u)) / time (t)
a = (v – u) /t
With the above formula, we can obtain the acceleration of the body as follow:
Initial velocity (u) = 5 m/s
Final velocity (v) = 17 m/s
Time (t) = 3 secs
Acceleration (a) =?
a = (v – u) /t
a = (17 – 5) /3
a = 12/3
a = 4 m/s²
Finally, we shall determine the force applied to the body as follow:
Force (F) = mass (m) x acceleration (a)
F = ma
Mass (m) = 20 Kg
Acceleration (a) = 4 m/s²
Force (F) =.?
F = ma
F = 20 x 4
F = 80 M.
Therefore, the force applied on the body is 80 N.
What could be used as another word for electrical potential
A.wattage
B.voltage
C.current
D.power
Answer:
hey mate
answer is probably voltage as per me
as
Explanation:
Voltage, electric potential difference, electric pressure or electric tension is the difference in electric potential between two points, which is defined as the work needed per unit of charge to move a test charge between the two points
A mass, M, is at rest on a frictionless surface, connected to an ideal horizontal spring that is unstretched. A person extends the spring 30 cm from equilibrium and holds it at this location by applying a 10 N force. The spring is brought back to equilibrium and the mass connected to it is now doubled to 2M. If the spring is extended back 30 cm from equilibrium, what is the necessary force applied by the person to hold the mass stationary there
Answer:
The necessary force applied by the person to hold the mass stationary there is 10 N
Explanation:
We are told that this person extends the spring 30 cm from equilibrium and holds it at this location by applying a 10 N force.
Thus, based on Hooke's law formula which is F = k Δx, we can say that the mass attached to the spring does not change the spring constant. Thus, the
same resistive spring force will still be in place and in turn, the same stretching force of 10N would still be required.
Thus;
The necessary force applied by the person to hold the mass stationary there is 10 N
Light, heat, electricity, sound are examples of
Answer: Energy
Explanation: Light, heat, electricity, sound are examples of energy
What do is mean by environment friendly behaviour?
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 :-)
Hi please may someone help me especially on the sketch part.
An object falls from a hovering helicopter and hits the ground at a speed of 30 m/s. How long does it take the object to reach the ground and how far does it fall? Sketch a velocity-time graph for the object (ignore air resistance).
Ignoring the air resistance it will take about 3 seconds for the object to reach the ground.We know that the acceleration due to gravity is 10m/s2.
We also know that the final velocity is 30 m/s while the initial velocity is 0 m/s
we can use the formulae for acceleration to calculate the time taken/
(final - initial velocity)/timetaken=10
(30-0)/timetaken=10
timetaken =30/10=3 seconds
Answer the following questions. 3 A student runs 2 m/s. What does this mean?
Answer:
2ms-¹ means that the body under consideration moves 2m in a second, and may be it will continue to move 2m in every 1 second, if there's no external unbalanced force acting on that body (those forces do include frictional forces). mark its brainlist plz. Kaneppeleqw and 6 more users found this answer helpful. Thanks 3.
Answer:
that the student has travels 2 meters every 1 second that passes
What is the difference between cytology and histology
Explanation:
what is the difference between cytology and histology
Histology involves the study of tissue and Cytology involves the study of cells, both of which are derived from various organs of the human body. The Histology laboratory is responsible for the preparation of tissue for diagnosis by Pathologists.
KINDLYY FASTT A uniform metre rule of mass 100 g is pivoted at the 60 cm mark. At what point on the meter rule should a mass of 50 g be suspended for it to balance horizontally?
Answer:
80 cm.
Explanation:
Since the metre rule is 1 m i.e 100 cm it means that the mass of the metre can be obtained at the 50 cm mark.
But the metre is pivoted at the 60 cm.
Please refer to the attached photo for details.
In the attached photo, y is the distance between the mark (that will balance the metre rule when a 50 g mass is hunged) and the pivot.
Thus, we can obtain the value of y as follow:
Anticlock wise moment = Clock wise moment
Anticlock wise moment = 100 × 10
Clock wise moment = y × 50
Anticlock wise moment = Clock wise moment
100 × 10 = y × 50
Divide both side by 50
y = (100 × 10) /50
y = 20 cm
Now, to obtain the mark, B that will balance the metre, we simply add 20 cm to 60 cm ie
B = 60 + 20
B = 80 cm
give an example of a balanced force and explain what makes it a balanced force
any person who opens the door he applies
Answer:
any person who opens the door he applies pulling force
I need help with this
Answer:
D, B, A, E, C
Explanation:
KE = m*g*h
PE = (1/2)m*v²
1. d
2. b
3. a
4. e
5. c
what is the function of eye lens of the human eye
Answer:
Lens of the human Eye is a important and one of that most complex sense organ.
Explanation:
Lens of the human eye it helps that in visualizing light and color perception and objects , glance on the human eye structure and function.
Sense organs are much pretty similar to the camera they help us see the objects clear.
A human eye is the 2.3 cm in diameter and all filled some fluid, and there are following parts in eye:- cornea, Retina , Lens ,Pupil , optic nerves.
cornea :- the cornea is the first transparent part of is called cornea, enters the light through the cornea.
Retina :-it is light sensitive layer that consists of nerve cells,then transmitted to the brain through nerves.
Lens:- behind the pupil there is a transparent structure called lens,it shape focus light on the retina.
Pupil:-it control the value of light that enters the human eye.
Optic nerves is are the two types :- (1) cones (2) Rods .
Answer:
It causes Light Rays to converge on the retina
Explanation:
I took the K12 Test
when an apple falls towards the earth the earth moves up to meet the apple. Is it true? If yes, why is the earth motion not noticeable ?
Answer:
Yes, this is true.
-- While the apple is falling, the same gravitational force acts on both the apple and the Earth.
-- The mass of the apple is somewhere in the neighborhood of 1/4 kg.
-- The mass of the Earth is about 5.972 x 10²⁴ kg.
-- Since the Earth has roughly 2.389 x 10²⁶ times as much mass as the apple has, the apple has roughly 2.389 x 10²⁶ greater acceleration than the Earth has, and moves roughly 2.389 x 10²⁶ times as far down as the Earth moves up, before they smack together.
-- That's why you don't notice the Earth's motion.
-- Also, you're standing on the Earth, moving up with it, toward the apple. Maybe it would be different if you were sitting on the apple, riding it down to the ground, and you were able to notice the motion of the ground coming up to meet you at a speed that's 0.00000000000000000000000000419 of YOUR speed.
Answer From Gauth Math
THE LENGTH OF A PENDULUM IS (1.5±0.01)m AND THE ACCELERATION DUE TO GRAVITY IS TAKEN AS (9.8±0.1)ms-² calculate the time period of the pendulum with uncertainty in it
Answer:
2.4583 ± 0.0207 seconds
Explanation:
The time period of a pendulum is approximately given by the formula ...
T = 2π√(L/g)
The maximum period will be achieved when length is longest and gravity is smallest:
Tmax = 2π√(1.51/9.7) ≈ 2.47903 . . . seconds
The minimum period will be achieved for the opposite conditions: minimum length and maximum gravity:
Tmin = 2π√(1.49/9.9) ≈ 2.43756 . . . seconds
If we want to express the uncertainty using a symmetrical range, we need to find half their sum and half their difference.
T = (2.47903 +2.43756)/2 ± (2.47903 -2.43756)/2
T ≈ 2.4583 ± 0.0207 . . . seconds
__
We have about 2+ significant digits in the given parameters, so the time might be rounded to 2.46±0.02 seconds.
Ken received a 66 on his first math exam, which counted for 20% of his final grade; he now believes that he won't be able to pass the class. His conclusion best illustrates a pessimistic outlook. the fight-or-flight response. problem-focused coping. relative deprivation.
Answer:
His conclusion best illustrates a pessimistic outlook.
Explanation:
As seen in the question above, Ken got 20% of his final grade in the first test he did for this class, that is, there will be other tests that can provide him to reach the grade needed to pass the class. However, even if there are possibilities, he believes that he will not pass the class, he does not have a positive and optimistic view of his future in this class and is sure that he will fail. This negative view of the future is an example of a pessimistic outlook.
Ploughing field with harrow pulled by a tractor is a modern technology
Ploughing field with harrow pulled by a tractor being a modern technology is true.
What is Technology?This involves the use of scientific knowledge to tackle different life problems and has different sectors.
Ploughing field with harrow pulled by a tractor involves machines and not manual labour which makes it a modern technology.
Read more about Technology here https://brainly.com/question/7788080
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give scientific reasons when the body falls freely to the ground its motion as the uniform acceleration
Answer:
When an object falls freely to the ground, its acceleration is uniform. Hint: When an object falls freely on the ground, the force of the gravity works on it. So the acceleration on the object is the acceleration due to gravity. So the acceleration is uniform on the freely falling body.
differniate between Magnetic force and electrostatic force
Answer:
magnetic force:
i) It is exerted by a magnet.
ii)Magnetic forces are always normal to the direction of the velocity of the charge it acts upon.
Electrostatic force
i) It is exerted by electrically charged body.
ii)Electric force are independent of the direction the charge moves in.
✌✌✌✌
why is heat produced when we rub our hands together
Answer:
friction
the rubbing of the surfaces create friction, giving off heat
Answer:
heat is produced by rubbing our hands together which cause friction and during the process you can feel heat.
high priority should be given for the development and use oc hydroelectricity justify with reason
Answer:
because hydroelectricity is generate from water and it is considered as a perpetual resources and produce the large capacity of electricity which helps in the indicator of development