Answer: the car that is moving downhill
Explanation:
How long must you wait (in half-lives) for a radioactive sample to drop to 2.10 % of its original activity?
Answer:
222/88 Ra
Explanation:
We have to wait 5.57 half lives for a radioactive sample to drop to 2.10 % of its original activity.
To find the tike taken for the activity, we need to know about radioactivity and half-life.
What is radioactivity?Radioactivity is the rate of decay of a radioactive substance with respect to time. Mathematically, radioactivity is given asR=R₀e^(-λ×t)
From the above expression time is given ast= 1/λ ln(R₀/R)
What is half-life?Half-life is the time taken for decay of radioactive sample to half of its initial value. Mathematically, half-life= ln2 / λWhat is the expression of time of activity in term of half-life?From the half-life expression, 1/λ=half-life/ln2.Putting the value of 1/λ in the expression of time of activity, we havet=(half-life/ln2)×ln(R₀/R)
What is the time for radioactive sample to drop to 2.10 % of its original activity?Here R=0.021R₀, so t= (half-life/ln2)×ln(R₀/0.021R₀)=5.57 half-lives
Thus, we can conclude that we have to wait 5.57 half lives for a radioactive sample to drop to 2.10 % of its original activity.
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Initial velocity of a car is 36 km/hr. Find the distance after one min, if it goes with acceleration 2m/s².
[A] 4000 m.
[B] 4200 m.
[C] 4400 m.
[D] 4600 m.
Answer:
[tex]\bf\pink{4200\:m}[/tex]Explanation:
Given :-[tex]\sf\red{ Initial \ velocity = 36km/hr = 10m/s}[/tex][tex]\sf\orange{ Acceleration = 2m/s^{2}}[/tex][tex]\sf\green{Time = 1\:min = 60\: sec}[/tex]To Find :-[tex]\sf\blue{Distance \: Travelled}[/tex]Formula used :-[tex]\sf\purple{s = ut + \dfrac{1}{2} at^{2}}[/tex]Where,
s = [tex]\bold{Distance}[/tex]t = [tex]\bold{Time }[/tex]u = [tex]\bold{ Initial \ velocity}[/tex]a = [tex]\bodl{Acceleration}[/tex]Solution :-[tex]\Rightarrow\:\:\rm{s = 10(60) + \dfrac{1}{\cancel{2}} \times \cancel{2} \times (60)^{2}}[/tex]
[tex]\Rightarrow\:\:\rm{s = 600+60\times 60}[/tex]
[tex]\Rightarrow\:\:\rm{s = 600 + 3600}[/tex]
[tex]\Rightarrow\:\:\rm{s = {\bf{\red{4200\:m}}}}[/tex]
Hence, [tex]\bf\green{(B)}[/tex] is the correct optionA Boeing 737—a small, short-range jet with a mass of 51,000 kg— sits at rest at the start of a runway. The pilot turns the pair of jet engines to full throttle, and the thrust accelerates the plane down the runway. After traveling 940 m, the plane reaches its takeoff speed of 70 m/s and leaves the ground. What is the thrust of each engine?
Answer:
67000N
Explanation:
We solve for the acceleration using the the 3rd constant-acceleration equation.
(Vx)f² = (Vx)i² + 2ax∆x
We have the displacement to be
∆x = Xf - Xi = 940m
Vx = 70m/s
The acceleration = (70m/s)²/2(940m)
= 4900/1880
= 2.61m/s²
From isaac newton's second law,
51000kg x 2.61m/s²
= 133,000N
The engines thrust is half of this value
Therefore thrust = 67000N or 67kN
A certain heat engine does 30.2 kJ of work and dissipates 9.14 kJ of waste heat in a cyclical process.
A) What was the heat input to this engine?
B) What was its efficiency?
Answer:
a) [tex]H_{in}=39.34 kJ[/tex]
b) Efficiency=76.77%
Explanation:
a)
In order to solve this problem, we can use the following formula:
[tex]H_{in}=H_{out}+W[/tex]
the problem provides us with all the necessary information so we can directly use the formula:
[tex]H_{in}=9.14kJ+30.2kJ[/tex]
[tex]H_{in}=39.34 kJ[/tex]
b) In order to find the efficiency, we can use the following formula:
[tex]Efficiency=\frac{W}{H_{in}}*100\%[/tex]
so we get:
[tex]Efficiency=\frac{30.2kJ}{39.34kJ}*100\%[/tex]
Efficiency=76.77%
Which of these statements is true about the International Space Station in orbit around the earth?
A) The space station exerts a force on the earth toward the space station.
B) The force of gravity produces the same acceleration for the earth and the space station. C) There is no gravity acting at the height of the space station.
D)The earth's gravity acts on the space station, but not the reverse.
Answer: b is probly correct beacuse all the others make no sence
The statement that is true about international space station is The force of gravity produces the same acceleration for the earth and the space station.
What is international space station?.International space station is a space station that is located at the lower part of the Earth's orbit . It is the third largest space object in the space and it is a multinational project that involves five different space agencies are NASA, Roscosmos, JAXA, ESA, and CSA.
Therefore, The statement that is true about international space station is The force of gravity produces the same acceleration for the earth and the space station.
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examples of sound to radiant energy
Answer:
Examples of Radiant Energy All Around You
The term radiant energy refers to energy that travels by waves or particles, particularly electromagnetic radiation such as heat or x-rays. Radiant energy is created through electromagnetic waves and was discovered in 1885 by Sir William Crookes. Fields in which this terminology is most often used are telecommunications, heating, radiometry, lighting, and in terms of energy created from the sun. Radiant energy is measured in joules.
Everyday Examples of Radiant Energy
Virtually anything that has a temperature gives off radiant energy. Some examples of radiant energy include:
•The heat emitted from a campfire
•Emission of heat from a hot sidewalk
•X-rays give off radiant energy
•Microwaves utilize radiant energy
•Space heaters produce radiant energy
•Heat created by the body can be radiant energy
•Lighting fixtures
√Home heating units
•Fixtures that convert solar energy to heat
•Visible light
•Gamma rays
•Radio waves
•Electricity
•A surface heated by the sun converts the energy of the light into infrared energy which is a form of radiant energy
•Cell phones utilize radiant energy to function
•Magnetic motor generators that utilize •neodymium magnets create radiant energy
•Audio signals that come to home or cars via radio waves
•Ultraviolet light
√Infrared radiation
•The light emitted from a campfire
•The light generated from a light bulb
•A heated brake disc giving off heat
•The heat from a grill used for cooking
•Water can reflect or absorb radiant energy
•Soil can absorb radiant energy
•Light from the sun
•Heat emitted from a bunsen burner
•Heat from an overused computer
•Heat caused by friction
•Heat emitted from a dryer
•The heat generated by a light bulb
•Heat generated through reflection of visible light
•A window reflects radiant energy
•Heat created from a stove or oven
•Heat emitted from a washing machine
Brianna pushes a 20 kg box with a force of 50N to achieve an acceleration of 2.5 m/s/s. In order to push a 30
kg box at the same acceleration, how much force will Brianna need to apply? She applies _ N of force.
Answer:
She applies 75N of force
Explanation:
F=ma
50=20(2.5)
F=30(2.5)
F=75 N
The current theory of the structure of the
Earth, called plate tectonics, tells us that the
continents are in constant motion.
Assume that the North American continent
can be represented by a slab of rock 5200 km
on a side and 35 km deep and that the rock
has an average mass density of 2700 kg/m².
The continent is moving at the rate of about
3.8 cm/year.
What is the mass of the continent?
Answer in units of kg.
Answer:
pt 1: [tex]m=1.66698*10^{21} kg[/tex]
Pt 2: [tex]KE=1212.23531 J[/tex]
Explanation:
Information Given: (p = density)
l = 5200km d = 35km p = 2700kg/[tex]m^{2}[/tex]
Part 1: Mass
Find volume [tex]V=(l)^2(d)[/tex][tex]V=(4.2*10^6)^2(35*10^3)[/tex][tex]V=61.74*10^{16}[/tex]Find Mass[tex]m=Vp[/tex][tex]m=(61.74*10^{16})(2700)[/tex][tex]m=1.66698*10^{21}[/tex]Part 2: Kinetic Energy
[tex]v=\frac{3.8cm}{yr}*\frac{m}{100cm}*\frac{yr}{365d}*\frac{d}{24hr}*\frac{hr}{3600s}[/tex][tex]v=1.20497*10^{-9}[/tex][tex]KE=\frac{1}{2}mv^2[/tex]
[tex]KE=\frac{1}{2} (1.66698*10^{21})(1.20497*10^{-9})^2[/tex]
[tex]KE=1212.23531 J[/tex]
Part 3: Jogger Speed
set up, because I don't have the mass :(
Information given:
[tex]KE_{jogger}[/tex]
[tex]KE=\frac{1}{2}mv^2[/tex][tex]v_{jogger} =\sqrt{\frac{2KE}{m_{jogger} } }[/tex]Input the valuesHope it helps :)
Which is the largest gas that occurs in our atmosphere?
Helium
Nitrogen
Other Gases
Oxygen
Answer:
OXYGEN
Explanation:brainlyist me
Answer:
Nitrogen
Explanation:
Oxygen is second
What does the phrase “constant velocity” indicate?
a. zero distance
b. zero acceleration
c. constant acceleration
d. deceleration
What do light and energy tell us about the universe?
need a paragraph
A 65-cm segment of conducting wire carries a current of 0.35 A. The wire is placed in a uniform magnetic field that has a magnitude of 1.24 T. What is the angle between the wire segment and the magnetic field if the force on the wire is 0.26 N?
a. 37°.
b. 43°.
c. 23°.
d. 53°.
e. 67°.
Answer:
e) 67°
Explanation:
the force on the wire can be calculated using the expression below
F = BILsinФ
But we are looking for the angle between the wire segment and the magnetic field, then we can make Ф the subject of the formula from the above expresion, then we have,
Ф =sin⁻¹ (F/BIL)
The parameters is defined as
I =current that is been carried by the wire= 0.35 A
Ф = angle between the wire segment and the magnetic field, which is the unknown?
L = length of the wire=65 cm
B = magnetic field = 1.24
F= force on the wire = 0.26 N,
Ф =sin⁻¹ (F/BIL)
Ф =sin⁻¹ X .....................eqn(#)
Where X= (F/BIL)
We can calculate for X= (F/BIL), from eqn(#) by substituting value of Force, Lenght and
magnetic field
X=(F/BIL)= 0.26/(1.24×0.35×0.65)
= 0.26/0.2821
=0.922
Then substitute X into eqn (Ф =sin⁻¹ X)
Then
Ф =sin⁻¹ (0.922)
Ф=66.42°
Ф=67° approximately
Therefore, the angle between the wire segment and the magnetic field is 67°
What is an easy way to encourage students to stay hydrated?
Let them know hydration improves performance.
Encourage them to drink water between each class.
Tell them to drink 8 glasses of water per day.
Have them track their hydration with a "water diary."
An easy way to encourage students to stay hydrated is to let them know hydration improves performance.
Drinking water is essential for our body system to function well. It helps in the regulation of the body temperature, the prevention of infections, as well as the delivery of nutrients to different parts of the body.
Staying hydrated is also vital in getting enough sleep and keeps the body in shape.
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6. What is the mass of a boy who is standing on top of a 1.5 meter high
wall and has 735 J of gravitational potential energy?
Answer:
m = 50 [kg]
Explanation:
The potential energy can be calculated by means of the following equation.
[tex]E_{p}=m*g*h[/tex]
where:
Ep = potential energy = 735 [J]
m = mass [kg]
g = gravity acceleration = 9.81 [m/s²]
h = elevation = 1.5 [m]
Now replacing:
[tex]735=m*9.81*1.5\\m = 50 [kg][/tex]
Which statement illustrates how progress in engineering has affected the natural environment?
A. Extracting mineral resources with modern mining equipment removes fertile topsoil.
B. Mining companies use modern equipment to extract mineral resources more efficiently.
C. Modern mining equipment has improved the health and safety of workers.
D. Modern mining practices provide materials that can be used for technological advances.
Correct answer is A
Answer:
A. Extracting mineral resources with modern mining equipment removes fertile topsoil.
Explanation:
Mining is defined as the process that involves the extraction of valuable minerals from large amounts of waste rock.
Progress in engineering has affected the natural environment and mining is one of the best examples of this. The use of modern mining equipment removes fertile topsoil and highly influences the fertility of the soil. It is hard to reconstruct topsoil and modern mining equipment continuously damaging soil fertility.
Hence, the correct answer is "A. Extracting mineral resources with modern mining equipment removes fertile topsoil."
Answer:
a
Explanation:
a pex
A 1.2 kg block of wood hangs motionless from strings. A 50 g bullet, traveling horizontally, strikes the block and becomes embedded inside the block. Immediately after the bullet becomes embedded in the block, the block is observed to have a speed of 8.0 m/s. What was the speed of the bullet before it hit the block?
A. 200 m/s.
B. 12 m/s.
C 98 m/s.
D 9,604 m/s.
E 57 m/s.
Answer:
A. 200m/s
Explanation:
Using the law of conservation of momentum expressed as;
m1u1 + m2u2 = (m1+m2)v
m1 and m2 are the masses of the object
u1 and u2 are the respective velocities
v is the common velocity
Given
m1 = 1.2kg
u1 = 0m/s (block is a stationary object)
m2 = 50g= 0.05kg
u2 = ?
v = 8.0m/s
Substitute the values into the formula and get u2 (speed of the bullet before hitting the block)
1.2(0)+0.05u2 = (1.2 + 0.05)(8)
0.05u2 = 1.25(8)
0.05u2 = 10
u2 = 10/0.05
u2 = 200m/s
Hence the speed of the bullet before it hit the block is 200m/s
find the base area of a cylinder with diameter 1m
Answer:
AB=0.79
Explanation:
hope this helped
How does reflection differ from refraction and diffraction?
Reflection is the only process in which the wave does not continue moving forward.
Reflection is the only process in which the wave slows down.
Reflection is the only process that involves a change in the wave.
Reflection is the only process that changes the direction of a wave.
Answer: Reflection is the only process in which the wave does not continue moving forward.
Explanation:
Reflection is a process in which the direction of the wave changes when it is exposed to a bounce off barrier. Refraction can be defined as the change in the direction of the wave when the wave passes through one medium to another. Diffraction is a process in which the direction of the wave changes when the wave passes through a particular opening near the barrier.
Answer:
Reflection is the only process in which the wave does not continue moving forward.
Explanation:
What would have to be the self-inductance of a solenoid for it to store 10.2J of energy when a 1.20A current runs through it?
Answer:
14.17H
Explanation:
Energy stored in an inductor is expressed as;
E = 1/2LI²
L is the inductance of the inductor
I is the current flowing through the inductor
Given
E = 10.2J
I = 1.20
Required
Inductance L
Substitute the given parameters into the formula;
10.2 = 1/2L(1.2)²
10.2 = 1/2*1.44L
10.2 = 0.72L
L = 10.2/0.72
L = 14.17H
Hence the self inductance of the solenoid is 14.17H
A frequency generator sends a 550Hz sound wave through both water and ice. What is the difference in wavelength between the wave produced in ice and the wave produced in water?
Answer:
3.1
Explanation:
use formula f = v/lambda
What is the acceleration of the the object during the first 4 seconds?
Answer:
Velocity (m/s) over time (s) graph
Velocity (m/s) over time (s) graph
We could write out our average acceleration as:
a = Δv/ Δta=Δv/Δta, equals, Δ, v, slash, Δ, t
a = (15 m/s - 0 m/s) / 0.2 seconds
a = 15 m/s / 0.2 seconds
a = 75 m/s / second
Explanation:
What this formula is telling us is that if we know the acceleration of an object, and the ... we can plug in our acceleration of 12.5 m/s2 for a, and 4 seconds for t.
Velocity (m/s) over time (s) graph
Velocity (m/s) over time (s) graph
We could write out our average acceleration as:
a = Δv/ Δta=Δv/Δta, equals, Δ, v, slash, Δ, t
a = (15 m/s - 0 m/s) / 0.2 seconds
a = 15 m/s / 0.2 seconds
a = 75 m/s / second
A fish swims to a depth of 50.00 meters in the ocean. Assuming the density of sea water is 1.0251.025 g·cm^{-3}g⋅cm −3 , calculate how much water pressure the fish is experiencing at this depth in units of kPa.
Answer:
The fish is experiencing a water pressure of 502.8 kPa.
Explanation:
The water pressure the fish is experiencing can be found as follows:
[tex]P = \rho gh[/tex] (1)
Where:
g: is the gravity = 9.81 m/s²
h: is the height (depth) = 50.0 m
ρ: is the seawater's density = 1.025 g/cm³
By replacing the above values into equation (1) we have:
[tex] P = \rho gh = 1.025 \frac{g}{cm^{3}}*\frac{1 kg}{1000 g}*\frac{(100cm)^{3}}{1 m^{3}}*9.81 m/s^{2}*50.0 m = 502.8 kPa [/tex]
Therefore, the fish is experiencing a water pressure of 502.8 kPa.
I hope it helps you!
The effect of gravity on a falling object can be modeled by a ball dropped from different heights. What is a limitation of this model?
A. Not all objects bounce, even though balls do.
B. Some balls float in water, while others sink.
C. The ball can be dropped from varying heights.
D. Friction with air also affects the fall of the object.
Correct answer is D
Answer:
D.
Explanation:
try it.. *lil uzi vert's voice*
The limitation of the model of a ball dropped from different heights is that friction with air also affects the fall of the object. Hence, option (D) is correct.
What is Galileo's Leaning Tower of Pisa experiment?According to a biography written by Galileo's student Vincenzo Viviani in 1654 and published in 1717, between 1589 and 1592, the Italian scientist Galileo Galilei, who was then a professor of mathematics at the University of Pisa, is said to have dropped two spheres with the same volume but different masses from the Leaning Tower of Pisa to show that their time of descent was independent of their mass. A few decades previously, Italian experimenters had already proven the fundamental tenet.
Galileo, it is said, discovered through this experiment that the items fell with the same acceleration, confirming his prediction and refuting Aristotle's theory of gravity in the process (which states that objects fall at speed proportional to their mass). The majority of historians believe it to have been more of a thought experiment than a physical test.
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if chilled coke and hot tea are
kept together tea cools down but ko gets warm why
A mover slides a refrigerator weighing 650 N at a constant velocity across the floor a distance of 8.1 m. The force of friction between the refrigerator and the floor is 230 N. How much work has been performed by the mover on the refrigerator?
Given :
A mover slides a refrigerator weighing 650 N at a constant velocity across the floor a distance of 8.1 m.
The force of friction between the refrigerator and the floor is 230 N.
To Find :
How much work has been performed by the mover on the refrigerator.
Solution :
Since, refrigerator is moving with constant velocity.
So, force applied by the mover is also 230 N ( equal to force of friction ).
Now, work done in order to move the refrigerator is :
[tex]W = Force\times distance\\\\W = 230 \times 8.1\ N\ m\\\\W = 1863\ N\ m[/tex]
Hence, this is the required solution.
Mike rides his horse with a constant speed of 20 km/h. How far can he travel in 4 hours?
Answer:
Mike can travel 80 Km in 4 hours
Engine 1 has an efficiency of 0.18 and requires 5500 J ofinput heat to perform a certain amount of work. Engine 2 hasan efficiency of 0.26 and performs the same amount of work. How much input heat does the second engine require?
Answer:
The input energy to engine 2 is [tex]E_2 = 3807.7\ J[/tex]
Explanation:
From the question we are told that
The efficiency of engine one is [tex]\eta_1 = 0.18[/tex]
The input energy required is [tex]E = 5500 \ J[/tex]
The efficiency of engine 2 is [tex]\eta_2 = 0.26[/tex]
Generally the workdone by the engine 1 is mathematically represented as
[tex]W_1 = E * \eta_1[/tex]
=> [tex]W_1 = 5500 * 0.18[/tex]
=> [tex]W _ 1= 990 \ J[/tex]
Generally the workdone by engine 2 is mathematically represented as
[tex]W _2= E_1 * \eta_2[/tex]
=> [tex]W _2 = E_1 * 0.26[/tex]
=> [tex]W_2 =0.26E_1[/tex]
From the question we are told that [tex]W_1 = W_2[/tex]
So
[tex]990 =W_2 =0.26E_1[/tex]
=> [tex]E_2 = 3807.7\ J[/tex]
The corect phase sequence shown
Gas, Liguid, Solid
Lqud, Gas, Solid
Sold, Liguid, Gas
Gas, Solid, Liquid
above i
Answer:
Explanation:
gas, liquid, soild
liquid, Gas, solid
Gas, Solid, liquid
turns into _____ energy (when plants convert into food)
Answer:
its called photosynthesis
Explanation:
when plants turn food into energy. Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy and stored in the form of starch which can be used later.
Answer:
The answer would be photosynthesis
Explanation:
In this case plants convert light energy (1) into chemical energy, (in molecular bonds), through a process known as photosynthesis. Most of this energy is stored in compounds called carbohydrates. The plants convert a tiny amount of the light they receive into food energy. :)
How was the Periodic Table of Elements developed and how are the elements arranged on it?
Answer:
In 1869 Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them.
Explanation:
Answer: Mendeleev first published a table of elements arranged according to increasing atomic masses. He noticed that some elements near each other had differing properties, but elements in vertical columns had similar properties. Moseley then rearranged the table according to atomic numbers and this eliminated the discrepancies found in Mendeleev’s attempt. Today’s version of the periodic table displays elements in order based on their atomic number; the atomic number indicates the number of protons within the atoms of a particular element. Rows are called periods and columns are called groups. Elements in the same group have similar properties. Elements are grouped into nine categories: noble gases, halogens, nonmetals, alkali metals, alkaline earth metals, transition metals, other metals, metalloids, and rare earth elements.