An Astronaut on the Moon drops a rock straight downward from a height of 1.25 meters. If the acceleration of gravity on the Moon is 1.62 meters per second squared, what is the speed of the rock just before it lands?
Answer:
Since the astronaut drops the rock, the initial velocity of the rock is 0 m/s
We are given:
initial velocity (u) = 0 m/s
final velocity (v) = v m/s
acceleration (a) = 1.62 m/s/s
height (h) = 1.25 m
Solving for v:
From the third equation of motion:
v²-u² = 2ah
replacing the variables
v² - (0)² =2 (1.62)(1.25)
v² = 1.62 * 2.5
v² = 4 (approx)
v = √4
v = 2 m/s
The speed of the rock just before it lands is 2 m/s
An underwater sound source emits waves of frequency 30 kHz in all directions. How does the intensity of the waves (in Watts/m2) vary with distance r from the source?
a) 1/r^3
b) 1/r^2
c) 1/r
d) None of above
When an underwater sound source emits waves of frequency 30 kHz in all directions, the intensity of the waves (in Watts/m2) vary with distance r from the source by the relation 1/r²
As the intensity mechanical sound wave is inversely proportional to the square of the distance from the source, therefore the correct option is B.
What is the Wavelength?Wavelength can be understood in terms of the distance between any two similar successive points across any wave for example wavelength can be calculated by measuring the distance between any two successive crests.
It is the total length of the wave for which it completes one cycle.
The intensity of a mechanical wave is inversely proportional to the square of the distance from the source.
An underwater sound source emits waves of frequency of 30 kHz in all directions, the intensity of the waves (in Watts/m2) varies with distance r from the source by the relation 1/r², therefore the correct option is B.
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A ball is thrown upward in the air with an initial velocity of 40 m/s. How long does it take to
reach back to the point it was thrown from?
Answer:
You need the definition of acceleration (a=Vf-Vi/t) and 1 equation of linear motion (deltaX = Vi×t + 1/2×a×t^2). Since you know a is constant (gravity) and you know your initial Vi to be 40 m/s and your final velocity Vf to be zero (maximum height), then you can use thhe definition of acceleration to find time.
-9.81m/s^2 = (0-40m/s)/t
t = (-40)/(-9.81) s
t = 4.077s
Now that you have time, you should know all but deltaX in the equation of linear motion.
dX = (40m/s)(4.077s) + (1/2)(-9.81m/s^2)(4.077s)^2
dX = (163.099m) — (81.549m)
dX = 81.55m
explain why a wrecking ball can destroy a building, but a yo-yo cant. Use the term kinetic energy in your explanation.
The kinetic energy of a body determines it's level of impact on the object in which it comes in contact with. Hence, the much larger kinetic energy exhibited by a wrecking ball compared to a yo-yo means that is has a much larger impact on a building than a yo-yo.
Kinetic Energy = 0.5mv²The kinetic energy of a body is a factor of it's velocity and mass as they are directly proportional.
The wrecking ball has a very large mass which is thousands of times larger than that of a yo-yo. Also, the velocity at which a wrecking ball is launched is higher than the velocity of a yo-yo.
This means that the kinetic energy of a wrecking ball is much higher than that of yo-yo. Hence, having much greater impact on a building compared to a yo-yo.
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Which shows the correct steps in the formation of an ionic bond between these atoms?
A magnesium atom accepts six electrons from the fluorine atoms → Each fluorine atom donates three of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom accepts two electrons from the fluorine atoms → Each fluorine atom donates one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion → Each fluorine atom becomes a -1 ion
Answer:
D) A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion → Each fluorine atom becomes a -1 ion
Explanation:
sorry if its a bit late
The correct steps in the formation of an ionic bond are A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion. The correct option is D.
What are ionic bonds?The electrical attraction between two ions with opposing charges creates an ionic bond, also known as an electrovalent bond, in a chemical molecule.
Ionic compounds are created by ionic bonds, while covalent bonds create covalent compounds. Ionic bonds are created by a complete transfer of electrons, whereas covalent bonds are created by sharing electrons.
Covalent bonds are weaker than ionic ones. Ionic compounds have higher melting and boiling points.
Therefore, the correct option is D.
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A cylinder of mass 250 kg and radius 2.60 m is rotating at 4.00 rad/s on a frictionless.
Two more identical nonrotating cylinders fall on top of the first. Because of friction
between the cylinders they will eventually all come to rotate at the same rate. What is this final angular velocity?
Answer:
The angular momentum of a cylinder, when it is rotating with constant angular velocity is Lini =Iωi
. When two cylinders are added to the rotating cylinder, which are identical in their dimensions, the moment of inertia of the entire system increases (since mass increases). The final moment of inertia will be 3I
Since friction exist, all the cylinders start rotating with same angular velocity, the new angular velocity can be calculated using conservation of angular momentum
Thus, Iωi =3Iωf ⟹ωf =ωi/3 = 0.33ωi
A coin is rolling across a table at 0.23 m/s. It rolls off the table and lands 0.15 meters away from the edge of the table. How high is the table? Show all your work.
Answer:
The table is 2.08 m high
Explanation:
Horizontal Motion
When an object is thrown horizontally with a speed vo from a height h, the range or maximum horizontal distance traveled by the object can be calculated as follows:
[tex]\displaystyle d=v\cdot\sqrt{\frac {2h}{g}}[/tex]
If we know the range d = 0.15 m and the speed v = 0.23 m/s, we can solve the above equation for h:
[tex]\displaystyle h=\frac{d^2\cdot g}{2v^2}[/tex]
[tex]\displaystyle h=\frac{0.15^2\cdot 9.8}{2\cdot 0.23^2}[/tex]
[tex]\boxed{h=2.08\ m}[/tex]
The table is 2.08 m high
The path of a projectile fired at an angle above the horizontal is best described as
Which atmospheric layer gets warmer as altitude increases and contains the ozone layer?
Answer:
stratosphere
Explanation:
In the stratosphere, temperature increases with altitude. The stratosphere contains the ozone layer, which protects the planet from the Sun's harmful UV radiation.
Stratosphere is the atmospheric layer which gets warmer as the altitude increases and contains the ozone layer.
What is Stratosphere?The stratosphere is a layer of the Earth's atmosphere. It is the second layer of the atmosphere as we go upward into the atmosphere height. The troposphere is the lowest layer of the globe, which is present right below the stratosphere. The next higher layer of the atmosphere above the stratosphere is the mesosphere.
In the stratosphere layer, the temperature increases with the increase in the altitude range. The stratosphere layer contains the ozone layer, which works in the protection of the planet from the Sun's harmful ultraviolet radiations which could lead to cancer.
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Are these bones axial, appendicular
or both?
Answer:
Axial and Appendicular Skeletons The axial skeleton forms the central axis of the body and consists of the skull, vertebral column, and thoracic cage. The appendicular skeleton consists of the pectoral and pelvic girdles, the limb bones, and the bones of the hands and feet. Figure 6.41.
Explanation:
7. A 2kg block is acted on by two forces F1 and F2 as shown in the diagram. If the magnitude of F1 = 13N and F2 = 11N. If the coefficient of kinetic friction is .23, find (A) The normal force exerted on it by the floor. (2 pts) (B) The acceleration on of the block (2 pts)
Answer:
A.) 17.04 N
B.) 10.76 m/s^2
Explanation:
Given that a 2kg block is acted on by two forces F1 and F2 as shown in the diagram. If the magnitude of F1 = 13N and F2 = 11N. If the coefficient of kinetic friction is .23,
A.) To find the normal force exerted on it by the floor, we need to first calculate the vertical forces of the ropes.
The vertical force on F1 = 13 sin 30
F1 = -6.5 N
The vertical force on F2 = 11 sin 21
F2 = 3.94
The resultant force = - 6.5 + 3.94
Resultant force = - 2.56
The normal force = mg - 2.56
The normal force = 2 × 9.8 - 2.56
The normal force = 19.6 - 2.56
The normal force = 17.04 N
(B) The acceleration on of the block will be achieved by first calculating the horizontal force.
For F1 = 13Cos 30
F1 = 11.26N
For F2 = 11 cos 21
F2 = 10.27
the resultant force = 11.26 + 10.27
Horizontal force = 21.53N
Force = mass × acceleration
21.53 = 2 × a
a = 21.53 / 2
Acceleration a = 10.76 m/s^2
Your are part of a team to help design the atrium of a new building.Your boss, the manager of the project, wants to suspend a 6.2 kg sculpture high over the room by hanging it from the ceiling using thin, clear fishing line (string) so that it will be difficult to see how the sculpture is held up. The only place to fasten the fishing line is to a wooden beam which runs around the edge of the room at the ceiling.The fishing line that she wants to use will hold 10 kg so she suggests attaching two lines to the sculpture to be safe. Each line would come from the opposite side of the ceiling to attach to the hanging sculpture. Her initial design has the first line making an angle of 12.67∘with the ceiling and the second line making an angle of 16.15∘ with the ceiling. She knows you took physics, so she asks you if her design can work.
How much force would the first line exert on the beam holding it up?
Assume that g=9.8 m/s−2.
Answer:
The answer is below
Explanation:
Given that the mass of the sculpture (m) = 6.2 kg, [tex]\theta_1=12.67^o,\theta_2=16.15^o[/tex]
[tex]Sum\ of\ horizontal\ force\ is\ zero\ hence:\\\\T_1cos(\theta_1)=T_2cos(\theta_2)\\\\T_1=\frac{T_2cos(\theta_2)}{cos(\theta_1)}\\ \\Sum\ of\ vertical\ force\ is\ zero:\\\\T_1sin(\theta_1)+T_2sin(\theta_2)=mg\\\\\frac{T_2cos(\theta_2)}{cos(\theta_1)}sin(\theta_1)+T_2sin(\theta_2)=mg\\\\T_2=\frac{mg}{\frac{cos(\theta_2)}{cos(\theta_1)}sin(\theta_1)+sin\theta_2} \\\\T_2=\frac{6.2*9.81}{\frac{cos(16.15)}{cos(12.67)}sin(12.67)+sin16.15} =123.1\ N\\\\[/tex]
[tex]T_1=\frac{T_2cos(\theta_2)}{cos(\theta_1)}=121.2\ N[/tex]
As part of their research on cell reproduction, Ms. Kelly's biology class designed various experiments to determine the best conditions for budding, or asexual reproduction, in common yeast cells. The students added sucrose as a source of food for the yeast and each group added water of a different temperature to the yeast-sugar mix. They used a light microscope to observe and count the yeast cells.
Based on the recorded data, what observation did the students make regarding the growth of yeast cells?
A) Once the temperature reached 50oC, the yeast died.
B) The size of individual yeast cells increased with an increase in temperature.
C) Increased temperature played no role in increasing the number of yeast cells.
D) The number of yeast cells increased as the temperature of the water increased.
1)
You travel east at 50 km/hr and then north at 75 km/hr. What is your Resultant Velocity in km/h?
(Remember the angle) (5pts)
Answer:
15
Explanation:
What is the rate of acceleration of a hammer whose head goes from moving -2 m/s (downward) to +0.5 m/s (upward) when it hits and bounces off a hard rock ? The actual bounce takes 0.025 seconds
Answer:
[tex]a=100\ m/s^2[/tex]
Explanation:
Given that,
Initial velocity, u = -2 m/s
Final velocity, v = =.5 m/s
Time, t = 0.025 s
We need to find the rate of acceleration of a hammer. Acceleration is equal to the change in velocity divided by the time taken.
[tex]a=\dfrac{v-u}{t}\\\\a=\dfrac{0.5-(-2)}{0.025}\\\\a=100\ m/s^2[/tex]
So, the acceleration of the jet is [tex]100\ m/s^2[/tex].
show answer No Attempt 50% Part (b) Calculate the non-relativistic speed of these electrons v in m/s.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The value is [tex]v = 9.18 *10^{6} \ m/s[/tex]
Explanation:
From question we are told that
The potential difference is [tex]\Delta V = 0.24 kV = 0.24 *10^{3} \ V[/tex]
Generally the the non-relativistic speed of these electrons is mathematically represented as
[tex]v = \sqrt{\frac{2 * e * \Delta V}{m} }[/tex]
Here m is the mass of an electron with value [tex]m = 9.11 *10^{-31 } \ kg[/tex]
e is the charge on an electron with value [tex]e = 1.60 *10^{-19} \ C[/tex]
So
[tex]v = \sqrt{\frac{2 * 1.60 *10^{-19} * 0.24 *10^{3} }{9.11*10^{-31}} }[/tex]
=> [tex]v = 9.18 *10^{6} \ m/s[/tex]
When the force applied to an object increases, the motion of the object
Answer:
Semen is the most important thing in the life cycle of life
In the periodic table, the number of valence electrons in each element decreases from left to right across each period.
Select one:
O True
O False
50 POINTS PLSS
Your car is initially at rest when your hit that gas and the car begins to accelerate at a rate of 2.857 m/s/s. The acceleration lasts for 15.5 s. What is the final speed of the car and how much ground does it cover during this acceleration?
Answer:I think the answer is 5.43 I don’t rlly know
Explanation:
Please help me with physics homework I just need help with C and D. Picture is included
Answer:
For C is B and for D is A
Explanation:
B because that's where the b car will do all the force to go up, and A because there the car doesn't have to do any force other than the natural, and it already brings that on it's own.
A car is pushed and travels 12 m. The same car is then pushed and it travels 15m. What
could have happened? Select 2 answers.
The mass was decreased
The force was increased
The force was decreased
The mass was increased
=========================================
Explanation:
If the force is kept the same, but the mass was decreased, then the car will travel further. The less mass an object has, the less inertia it has. Inertia is the tendency for the object to stay at rest if it's initially at rest (or the tendency for the object to stay in motion if already in motion).
If the mass is kept the same, but the force was increased, then the object will travel further than before. The same idea applies as discussed in the last paragraph.
------
If the force was decreased and mass kept the same, then there is less push, which results in the object traveling a shorter distance. If the mass is increased but the force kept the same, then the object moves a shorter distance because there's more inertia to overcome. There are more particles needed to be moved and they resist motion if at rest.
can you pls give a question about science. like why does the sky blue? PLS HELPPP ASAP
A rock climber is going up a narrow space between two vertical rocks. The distance between the rocks allows the climber to brace herself using friction, where her feet are flat and in contact with one rock to the left, and her legs are straight horizontal and her back is flat against a rock on the right. The coefficient of static friction between her shoes and the rock on the left is 1.2, and between the rock at right and her back is 0.8. The climber relaxes until she is on the verge of slipping on both sides.
(a) Draw a FBD for the climber
(b) What fraction of her weight is supported by the frictional force on her shoes?
Answer: b
Explanation:
The most interpersonal constructive passion response to relational conflict is..
Answer:
loyalty
Explanation:
Can someone please help me
Answer:
grams= 4.8e-5
kilograms= 4.8e-8
centigrams= 0.0048
dekagrams= 4.8e-6
Explanation:
Newton’s third law says that every time there is an interaction force, there is also a force that is ______________________ in size and acts in the ____________________________ direction .
Answer:
equal, opposite
Explanation:
Newton’s third law says that every time there is an interaction force, there is also a force that is equal in size and acts in the opposite direction .
Which of the following is not a part of the appendicular skeleton
a. femur
b. scapula
c.phalanges
d.hyoid
Answer:
Hyoid
Explanation:
The hyoid is located in the neck area, not the limbs.
PLEASE PLEASE HELP PICTURE INCLUDED
Answer:
an electro magnet is technology contain at least one permanent magnet
A rubber cord catapult has cross-sectional area
25mmand initial length of rubber cord is 10c.
Its is stretched to 5cm and then released to
project a missile of mass 5gm. Taking
Yubber = 5x108N/m² velocity of projected
missile is :
(1) 20ms -
(2) 100ms
(3) 250ms
(4) 200ms)
WHat is the correct definnition for recovery heart rate ?
Answer:
when your heart rate is not high than normal or lower than normally
Explanation:
Recovery heart rate is when your heart recovers from a certain heart rate eg high heart rate or even low heart rate this means you heart is now functioning normally .
Answer:
Number of beats per minute the heart drops after exercise.