Answer:
The car stops in 7.78s and does not spare the child.
Explanation:
In order to know if the car stops before the distance to the child, you take into account the following equation:
[tex]x=x_o+v_ot-\frac{1}{2}at^2[/tex] (1)
vo: initial speed of the car = 45km/h
a: deceleration of the car = 2 m/s^2
t: time
xo: initial distance to the child = 25m
x: final distance to the child = 0m
It is necessary that the solution of the equation (1) for time t are real.
You first convert the initial speed to m/s, then replace the values of the parameters and solve the quadratic polynomial for t:
[tex]45\frac{km}{h}*\frac{1h}{3600s}*\frac{1000m}{1km}=12.5\frac{m}{s}[/tex]
[tex]0=25+12.5t-2t^2\\\\2t^2-12.5t-25=0\\\\t_{1,2}=\frac{-(-12.5)\pm \sqrt{(-12.5)^2-4(2)(-25)}}{2(2)}\\\\t_{1,2}=\frac{12.25\pm 18.87}{4}\\\\t_1=7.78s\\\\t_2=-1.65s[/tex]
You take the first value t1 because it has physical meaning.
The solution for t is real, then, the car stops in 7.78s and does not spare the child.
What are some of the major differences between the ancient Olympics and modern-day Olympics? List and describe at least two differences.
Answer:
-Women are now allowed to participate in the Olympics unlike before when it was only men allowed.
-Modern Olympic Games include many more events. There are more than 20 different sports and almost 300 events in the modern games, while the first Olympics only had running.
-The Olympics are held every two years. While the ancient Olympics were originally held every four years.
-Athletes from countries around the world participate in the modern Olympics unlike in the ancient Olympics where only athletes from ancient Greece competed.
Explanation:
Edmentum Plato answer (i already reworded most of it so you don't have to) <33
During the warm-up and your scheduled physical activity, what was the weather like? Did the
temperature or conditions affect how much water you drank? How?
Answer: I did these exercises outdoors. The weather was hot and humid, so I drank about two cups of water during the workout. I also drank a cup of water about an hour before I started. Yes, the weather most definitely affected how much I drank.
Explanation: Edmentum
An ideal gas initially at 300 K undergoes an isobaric expansion at 2.50 kPa. If the volume increases from 1.00 m3 to 3.00 m3 and 12.5 kJ is transferred to the gas by heat, what are a. the change in its internal energy and b. its final temperature?
Answer:
a) [tex] \Delta U = 7.5 kJ [/tex]
b) [tex]T_{f} = 900 K [/tex]
Explanation:
a) To find the change in its internal energy (U) we need to use the following equation:
[tex] \Delta U = W + Q [/tex]
Where:
W: is the work done on the system
Q: is the energy transferred into the system by heat = 12.5 kJ
Since we have an isobaric expansion, the work is:
[tex] W = - P\Delta V = - P(V_{f} - V_{i}) [/tex]
Where:
[tex]V_{f}[/tex]: is the final volume = 3.00 m³
[tex]V_{i}[/tex]: is the initial volume = 1.00 m³
P: is the pressure = 2.50 kPa
[tex] W = -P(V_{f} - V_{i}) = -2.5 \cdot 10^{3} Pa(3.00 m^{3} - 1.00 m^{3}) = -5.00 \cdot 10^{3} J [/tex]
Now, we can find the change in its internal energy:
[tex] \Delta U = W + Q = -5.00 \cdot 10^{3} J + 12.5 \cdot 10^{3} J = 7.5 \cdot 10^{3} J [/tex]
b) The final temperature can be found as follows:
[tex] \frac{V_{i}}{V_{f}} = \frac{T_{i}}{T_{f}} [/tex]
[tex] T_{f} = \frac{T_{i}*V_{f}}{V_{i}} = \frac{300 K*3.00 m^{3}}{1.00 m^{3}} = 900 K [/tex]
Hence, the final temperature is 900 K.
I hope it helps you!
Wings of a bird what kind of motion is it
Answer:
linear motion
Explanation:
the birds in the sky show oscillatory motion when they flap their wings
When Emma pushes a bag with a force of 27 newtons, the coefficient of kinetic friction between the bag and the floor is 0.23. What is the normal force acting on the bag by the floor? A. 0.085 newtons B. 27 newtons C. 2.7 × 102 newtons D. 1.2 × 102 newtons
Answer:
D. 1.2 × 102 newtons
Explanation:
The computation of the normal force acting on the bag is shown below:
It could find out by applying the following formula
Normal force = Force ÷ coefficient of kinetic friction
where,
Force is 27 newtons
And, the coefficient of kinetic friction is 0.23
Now placing these values to the above formula
So, the normal force is
= 27 newtons ÷ 0.23
= 117.39 N
Therefore the correct option is D.
As a motorcycle takes a sharp turn, the type of motion that occurs is called _______________ motion.
Answer:
circular motion
Explanation:
As a motorcycle takes a sharp turn, the type of motion that occurs is called circular motion.
Circular motion is a movement of an object along a circular path. As this motorcycle makes the sharp turn, it is acted upon by a centripetal force which directs the motorcycle towards the center.
Therefore, circular motion is the correct answer to the question.
Answer:
Circular Motion
In 2000, a 20-year-old astronaut left Earth to explore the galaxy; her spaceship travels at 2.5 x 10^8 m/s. She returns in 2040. About how old will she appear to be?
Answer:
42.11 years old
Explanation:
Given that:
In 2000, a 20-year-old astronaut left Earth to explore the galaxy; her spaceship travels at 2.5 x 10^8 m/s. She returns in 2040
To find her age we use:
[tex]\Delta t_m=\frac{\Delta t_s}{\sqrt{1-\frac{v^2}{c^2} } }\\[/tex]
Δtm is time interval for the observer stationary relative to the sequence of
events = 2040 - 2000 = 40 years
Δts is is the time interval for an observer moving with a speed v relative to the sequence of event
v = velocity = 2.5 x 10^8 m/s
c = speed of light = 3 x 10^8 m/s
[tex]\Delta t_s=\Delta t_m}{\sqrt{1-\frac{v^2}{c^2} } }\\\Delta t_s=40\sqrt{1-\frac{(2.5*10^8)^2}{(3*10^8)^2}}\\\Delta t_s=22.11\ yr[/tex]
Here age in 2000 is 20 year, therefore when she appear she would be 20 year + 22.11 year = 42.11 years old
write examples of adaptation in mangrove .?
what are the adaptation of rainforest.?
Answer:
example of adaptation in mangrove
Mangroves are salt-tolerant trees, also called halophytes, and are adapted to life in harsh coastal conditions. They contain a complex salt filtration system and complex root system to cope with salt water immersion and wave action. They are adapted to the low oxygen conditions of waterlogged mud.
adaptation of rainforest
Many animals have adapted to the unique conditions of the tropical rainforests.
hope this can help you
One of the key disadvantages of buying fitness equipment is __________. A. privacy B. flexibility C. maintenance D. choice Please select the best answer from the choices provided. A B C D
Answer:
C. maintenanceExplanation:
I personally believe one key disadvantages is the cost of maintaining the equipment unlike the gym where you have to subscribe for the month or the year and forget about anything, owning the gym equipment comes with the extra cost and responsibilities of maintenance to the owners.
Answer:
C
Explanation:
Edge 2020
Two forces of magnitudes 8N and 15N act at a point,if the resultant force is 17N,the angle between forces is equal to:
Answer:
The resultant of two vectors:
P
and
Q
is given by
R=
P
2
+Q
2
+2PQcosθ
where, P and Q are magnitudes of two vectors and θ is the angle between two vectors.
Here θ=? P=8N Q=15N R=17N
Therefore,
17=
8
2
+15
2
+2×8×15cosθ
289=64+225+240cosθ
289=289+240cosθ
289−289=240cosθ
cosθ=0
cosθ=cos90
θ=90
0
Explanation:
WHAT IS PHYSICS? OUTLINE THE BRANCHES OF PHYSICS PHYSICS IS AN ESSENTIAL SUBJECT, WHY DO YOU STUDY IT?
i will give brainliest
Answer:
Explanation:
Physics is the natural science that studies matter, its motion and behaviour through space and time and the related entities of energy and force The braches of physics : classical mechanics thermodynamics and statistical mechanics electromagnetism and photons relativistic mechanics quantum mechanics, atomic physics and molecular physics optics condensed matter physics high-energy particle physics and nuclear physics We must study physics to understand how universe workswhat is acceleration???
Answer:
The rate at which velocity changes.
Explanation:
Acceleration is when motion changes, it is the rate at which velocity changes.
Answer:
Acceleration is defined as change in velocity per unit time.The increase in velocity per unit time is called acceleration.
Hope this is helpful for you.
write the chemical formulae for; nitrogen monoxide, hydrochloric acid, barium phosphate, ammonium hydroxide,nitric acid
Answer:
Nitrogen Monoxide = NOHydrochloric Acid = HCLBarium Phosphate = (Ba) 3{(Po)4}Ammonium Hydroxide = (NH) 4(OH) Nitric Acid = H(NO)3When electrical energy is used what type of energy is also produced and considered to be waste energy?
Answer:
electrical energy is energy derived from electric potential energy or kinetic energy. when loosely electrical energy refers to energy that has been converted from electric potential energy
Answer:
electrical energy is energy derived from electric potential energy or kinetic energy. when loosely electrical energy refers to energy that has been converted from electric potential energy
Explanation:
Find vertical and horizontal displacement. Please help. 10 points. Thank you.
Explanation:
horizontal velocity = 30 x Cos45 = 19.48m/s
to find horizontal displacement
horizontal displacement = horizontal velocity x timehorizontal displacement = 19.48 x 2 = 38.96mvertical velocity = 30 x Cos45 = 22.81m/s
vertical displacement = vertical velocity x time
vertical displacement = 22.81 x 2 = 45.62m
Answer:
Displacement after two seconds
= <Dx,Dy> = <42.426, 1.593> m to three decimal places
Explanation:
Given:
arrow shot at 30m/s and 45 degrees with horizontal.
Hit bull's eye after 2 seconds.
Find horizontal and vertical displacements.
Vx = 30cos(30) m/seconds constant velocity
therefore
Dx = Vx*t = 30cos(30) m/s * 2 s = 60 cos (45) = 42.426 m
Vy = 30 sin(45) m/s
Dy = Vy*t + a(t^2) /2
= 30*sin(45) -9.81(2^2)/2 (g is accelerating downwards, so negative)
= 1.593 m
The net displacement after 2 seconds is
D = <Dx,Dy> = <42.426, 1.593> m to three decimal places
I will give Brainliest to whoever can answer!!!!
If the phase of the vibrating sources was changed so that they were vibrating completely out of phase, what effect would this have on the interference pattern?
Answer:
The nodes and anti nodes would reverse roles.
Explanation:
I believe it has to do with the path differences. If waves are in phase, then the path differences are such that the waves reach the screen with crests superimposing crests and troughs superimposing troughs. This happens when the periods of each wave are equal or the paths themselves differ by a whole number multiple of the wavelength (λ, 2λ, 3λ, ...).
Now make these waves out of phase. Then half of the waves will travel half a wavelength farther than the rest. So the path difference will be 0.5λ, 1.5λ, 2.5λ, ....
A physicist is designing a cyclotron to accelerate protons to one-tenth the speed of light. The magnetic field will have a strength of 1.6 T. (a) Determine the rotational period (in s) of the circulating protons. s (b) Determine the maximum radius (in m) of the protons' orbit
Answer:
(a) T = 4.09*10^-8 s
(b) r = 0.19m
Explanation:
(a) In order to determine the rotational period of the protons, you first calculate the angular speed of the proton. You use the following formula for the radius of the trajectory described by the electron in a region with a constant magnetic field:
[tex]r=\frac{mv}{qB}[/tex] (1)
m: mass of the proton = 1.67*10^-27 kg
q: charge of the proton = 1.6*10⁻19C
B: magnitude of the magnetic field = 1.6T
v: speed of the proton = 0.1c = 0.1(3*10^8m/s) = 3*10^7m/s
The angular speed of the proton is v/r, then, you solve for w in the equation (1) and replace the values of the parameters:
[tex]\omega=\frac{v}{r}=\frac{qB}{m}\\\\\omega=\frac{(1.6*10^{-19}C)(1.6T)}{1.67*10^{-27}kg}=1.53*10^8\frac{rad}{s}[/tex]
The rotational period T is:
[tex]T=\frac{2\pi}{1.53*10^8rad/s}=4.09*10^{-8}s[/tex]
(b) The radius of the protons' orbit is calculated by using the equation (1):
[tex]r=\frac{(1.67*10^{-27}kg)(3*10^7m/s)}{(1.6*10^{-19}C)(1.6T)}\\\\r=0.19m[/tex]
The radius of the protons' orbit is 0.19m
Which type of wave tables faster through solids than it does through gases
A- electromagnet waves
B- reverse waves
C- longitudinal waves
D- periodic waves
Answer:peroidic waves
Explanation:
The average battery in a car supplies a current of 3.5 A from a
12.6 V battery to the engine. How much power is consumed by
the engine?
Answer:
44.1 W
Explanation:
Power = Voltage x current
(P = VI)
P = 12.6 x 3.5
P = 44.1 W
Which of the following is a vector quantity? A.speed B.weight C.distance travelled D.mechanical energy
Answer:
mechanical energy
Explanation:
it is a vector energy
why do we generally hear a thunder when there is a Bolt of lightning
Please answer me fast
Answer:
Explanation:
When a lightning bolt travels from the cloud to the ground it actually opens up a little hole in the air, called a channel. Once then light is gone the air collapses back in and creates a sound wave that we hear as thunder. The reason we see lightning before we hear thunder is because light travels faster than sound!
Answer:
light travels faster than sound
Explanation:
A garrafa térmica (também conhecida como "vaso de Dewar") é um dispositivo extremamente útil para conservar, no seu interior, corpos (essencialmente líquidos) em altas temperaturas, minimizando trocas de energia com o ambiente, geralmente mais frio. Uma garrafa térmica contém água a 60 o C. O conjunto garrafa térmica + água possui capacidade térmica C=80 cal/o C. O sistema é colocado sobre uma mesa e, após um intervalo considerável de tempo, a sua temperatura diminui para 55 o C. Nesse caso, conclui-se que o sistema formado pela garrafa térmica e pela água no seu interior: a) perdeu 400 cal. B) ganhou 404cal. C) perdeu 4 850 cal. D) ganhou 4 850 cal. E) não trocou calor com o meio externo.
Answer:
A opção A está correta.
O sistema formado pela garrafa térmica e a água perde 400 cal de calor para o meio ambiente.
Option A is correct.
The system formed by the thermos and the water loses 400 cal of heat to the environment.
Explanation:
Quando a temperatura de um sistema reduz, fica claro que o sistema perdeu calor ou energia térmica. Como a temperatura é um dos indicadores mais claros disso, esta conclusão é hermética e correta.
Mas, para saber a quantidade de calor perdida para o meio ambiente, agora fazemos alguns cálculos de energia térmica.
Transferência de calor de ou para o sistema de água e garrafa térmica = c × ΔT
c = capacidade térmica do sistema de água e garrafa térmica = 80 cal /°C
ΔT = Alteração da temperatura do sistema de água e garrafa térmica = (temperatura final) - (temperatura inicial) = 55 - 60 = -5°C
Calor transferido = 80 × -5 = -400 cal.
O sinal de menos mostra que o calor é transferido para fora do sistema, ou seja, o calor é perdido no sistema.
Espero que isto ajude!!!
English Translation
The thermos (also known as "Dewar vase") is an extremely useful device to conserve bodies (essentially liquid) at high temperatures, minimizing energy exchanges with the environment, which is generally colder. A thermos contains water at 60 o C. The thermos + water set has a thermal capacity of C = 80 cal / o C. The system is placed on a table and, after a considerable period of time, its temperature decreases to 55 o C. In this case, it is concluded that the system formed by the thermos and the water inside:
a) lost 400 cal. B) gained 404cal. C) lost 4 850 cal. D) gained 4 850 cal. E) did not exchange heat with the external environment.
Solution
When a system's temperature reduces, it is clear to conclude that the system has lost heat or thermal energy. Since temperature is one of clearest indicators of this, this conclusion is airtight and correct.
But, to know the amount of heat lost to the environment, we now do some thermal energy calculations.
Heat transferrred from or to the water and thermos system = c × ΔT
c = heat capacity of the water and thermos system = 80 cal/°C
ΔT = Change in temperature of the water and thermos system = (final temperature) - (initial temperature)
= 55 - 60 = -5°C
Heat transferred = 80 × -5 = -400 cal.
The minus sign shows that the heat is transferred out of the system, that is, the heat is lost from the system.
Hope this Helps!!!
Reto: Aníbal desea construir una carpa de base hexagonal de 1,40 m de altura. El vértice de la base es de 0,80m y la longitud de la arista lateral mide 1,80m. ¿cuanto de tela necesito para cubrir la superficie lateral de la carpa? ¿cuanto de tela necesito para cubrir la base de la pirámide, que es un hexágono regular? Cuál es el volumen de la pirámide? ¿cuál es el área total de la pirámide?
Answer:
1.- para cubrir la superficie lateral 4.32 metros²
2.- Area de la base 2.15 metros²
3.- Volumen 1 m³
4.- Area total 6.47 metros²
Explanation:
El área lateral sera calcular el area de seis triangulos iguales cuya base es
0.80 de base x 6 lados = 4.80 metros perimetro de la base
4.80 perimetro de base x 1.80 arista lateral / 2 = 4.32m2
Area de la base:
Perímetro x Apotema / 2
Siendo la Apotema la altura de los triangulos que componen un hexagono calculada utilizando el teorema de pitágoras:
[tex]\sqrt{0.8^2 + (0.8/2)^2} = Apotema[/tex]
Apotema = 0.894427191
Area: 4.80 x 0.894427191 / 2 = 2.146625258
sumando el area de la base mas el area lateral se obtiene el area total
2.15 + 4.32 = 6.47 metros
Volumen de la pirámide:
Area de la Base x Altura / 3
2.15 x 1.40 / 3 = 1.00333 m3
A train moves at a constant velocity of 50 km/hHow far will it move in 0.5 h?
A. 10 km
B. 45 km
C.25 km
D. 20 km
Answer:
C
Explanation:
[tex]\dfrac{50km}{h}\cdot 0.5h= \\\\\\50km\cdot 0.5=25km[/tex]
Therefore, the correct answer is choice C. Hope this helps!
The correct answer is C.
It is C because .5 h is equal to 30 minutes. So half of 50 km is 25 km(Divided by 2)
Two wires of circular cross section are made of the same metal. Wire 1 has radius rr and length LL; wire 2 has radius 2r2r and length 2L2L. The potential difference between the ends of the wire is the same for both wires. Find the ratio of the resistance of wire 2 to the resistance of wire 1.
Answer:
Ratio of wire 2 to wire 1 is 0.5 : 1
Explanation:
Wire 1:
length = L
radius = r
Wire 2:
length = 2L
radius = 2r
Resistance of a conductor varies directly as the length and inversely as the cross sectional area. Mathematically
[tex]R = \frac{pl}{a}[/tex]
l = length of conductor
a = cross sectional area of the conductor
p = resistivity of the material with which the conductor is made.
since we are considering the same material, we can ignore the resistivity of the wire.
For wire 1
cross sectional area = [tex]\pi r^{2}[/tex]
therefore,
resistance R = [tex]\frac{L}{\pi r^{2} }[/tex]
For the second wire 2
cross sectional area = [tex]4\pi r^{2}[/tex]
therefore,
resistance R = [tex]\frac{2L}{4\pi r^{2} }[/tex]
Ratio of wire 2 to wire 1 will be
[tex]\frac{2L}{4\pi r^{2} }[/tex] ÷ [tex]\frac{L}{\pi r^{2} }[/tex] = [tex]\frac{2L}{4\pi r^{2} }[/tex] x [tex]\frac{\pi r^{2} }{L}[/tex]
Ratio of resistance of wire 2 to wire 1 = 2/4 = 0.5 : 1
difference between uniform velocity and variable velocity .
Answer:
If a body covers equal displacement in equal interval of time,however small may be the body is said to have uniform velocity. If a body covers in equal displacement in equal interval of time is called variable velocity.
Dominic made the table below to organize his notes about mixtures.
Properties of Mixtures
has no set composition
must have more than one state of matter
must have more than one substance
What mistake did Dominic make?
The title should read "Properties of Solutions" because some mixtures do not have all of the properties listed.
There is a definite recipe to make each mixture, so the composition of a mixture is set.
Although it is possible to have more than one state, it is also possible to have only one state.
A single substance can be used to make a mixture if the substance is composed of more than one element.
Answer:
Althought it us possible to have more then one state, it's also possible to have only one state of matter
Explanation:
You can make solutions of only one state if matter, for example , it two liquids can be mixed to form a solution they are called miscible.
Answer:
The correct answer is C.) Although it is possible to have more than one state, it is also possible to have only one state.
Explanation:
I just did the test on edge and got it right
Who found Uranus? Name?
Answer:William Herschel found the seventh planet now known as uranus
<!> Brainliest is appreciated! <!>
Explanation:
Answer:
William Herschel
Explanation:
Which of the following statements are true (mark all that apply) primordial nucleosynthesis produced all of the elements heavier than helium chemical composition of our solar system matches the chemical composition of the Milky Way some of the stars in the Milky Way may be older than the Milky Way your body contains a lot of helium nearly all atoms of elements heavier then helium were produced through nuclear fusion in stellar interiors and through reactions that occur during explosions that massive stars undergo at the ends of their lives or during mergers of stellar remnants called neutron stars some of the oldest galaxies are about 13.2 billion years old nucleosynthesis is a process through which the atoms of various elements are produced you're mainly made of hydrogen
Answer:
The correct options are;
1) The chemical composition of our solar system matches the chemical composition of the Milky Way
2) Nearly all atoms of elements heavier than helium were produced through nuclear fusion in stellar interiors and through reactions that occur during explosions that massive stars undergo at the ends of their lives or during mergers of stellar remnants called neutron stars
3) Some of the oldest galaxies are about 13.2 billion years old
4) Nucleosynthesis is a process through which the atoms of various elements are produced
5) You re mainly made of hydrogen
Explanation:
1) There are dependencies between chemical composition of stars and planets and the same distribution of chemicals we have in our Solar system have been observed to be present in varying resemblance through out the Milky Way
2) The formation of heavier elements are believed to have been formed by astrophysical fusion processes
3) The oldest known object (and hence the galaxy where the star resides), is from a distant star known as GRB 090423 which is about 13 billion years old
4) New atomic nuclear are created by the process of protons and neutrons by the process of nucleosynthesis
5) 62%of the atoms in the body are hydrogen atoms.
A machine is 40 % efficient. The total energy supplied to the machine is 4 kJ. Calculate how much useful energy can be transferred.
Answer:
1.6 kJ
Explanation:
0.40 (4 kJ) = 1.6 kJ