Answer:
2.1 seconds
Explanation:
let D represent the height in meters
let g represent gravity in meters per second squared
let t represent time in seconds
D= -42 meters (negative because it falls down)
g= -9.8m/s^2
t= [tex]\frac{-42 meters}{9.8 m/s^2}[/tex]
this gives t= 4.2857 s^2
the meter units cancel out in the division
now we must simplify the units to singular seconds so...
[tex]\sqrt{4.3 s^{2} }[/tex] which simplifies to [tex]\sqrt{4.3}[/tex] x [tex]\sqrt{s^{2} }[/tex]
this equals 2.1 seconds
Two boys X and Y each have the same total weight
and are standing on soft ground.
Which boy is more likely to sink into the soft ground and
why?
boy more
likely to sink
pressure on soft
ground
А
Х
larger than Y
B
Х
smaller than Y
C
Y
larger than X
D
Y
smaller than X
Answer:
the child with the smallest area will be the one who sinks
Explanation:
The child who will sink to the ground is the one who exerts the greatest pressure on the ground, even though the force, which in this case is equal to the weight, is equal.
Pressure is defined by
P = F / A
in this case the strength of the children is their weight
F = W
P = W / A
therefore the pressure changes are in the area of contact with the ground, the child with the smallest area will be the one who sinks
A 117 kg horizontal platform is a uniform disk of radius 1.61 m and can rotate about the vertical axis through its center. A 62.5 kg person stands on the platform at a distance of 1.05 m from the center, and a 28.3 kg dog sits on the platform near the person 1.43 m from the center. Find the moment of inertia of this system, consisting of the platform and its population, with respect to the axis.
Answer:
I_syst = 278.41477 kg.m²
Explanation:
Mass of platform; m1 = 117 kg
Radius; r = 1.61 m
Moment of inertia here is;
I1 = m1•r²/2
I1 = 117 × 1.61²/2
I1 = 151.63785 kg.m²
Mass of person; m2 = 62.5 kg
Distance of person from centre; r = 1.05 m
Moment of inertia here is;
I2 = m2•r²
I2 = 62.5 × 1.05²
I2 = 68.90625 kg.m²
Mass of dog; m3 = 28.3 kg
Distance of Dog from centre; r = 1.43 m
I3 = 28.3 × 1.43²
I3 = 57.87067 kg.m²
Thus,moment of inertia of the system;
I_syst = I1 + I2 + I3
I_syst = 151.63785 + 68.90625 + 57.87067
I_syst = 278.41477 kg.m²
Q010) A well in which the water rises on its own to a level above its aquifer Group of answer choices is the result of pressure within a confined aquifer that creates a potentiometric surface. is called an ordinary well. always pushes water higher than the ground surface. cannot be used for commercial or public use, as the water is under too much pressure.
Answer:
The result of pressure within a confined aquifer that creates a potentiometric surface
Explanation:
There are conditions under the Earth's surface, where porous rock layers are tilted and also have a confining, less porous, rock layer about the their boundary, forming a confined aquifer. The existing pressure in the aquifer is therefore confined within the water and the porous rock layer, such that drilling into the pressurized aquifer leads to the water rising under the pressure existing in the aquifer, to a potentiometric surface which is above the actual underground level of the aquifer
Two manned satellites approach one another at a relative velocity of v=0.190 m/s, intending to dock. The first has a mass of m1=4.00×103 kg and the second a mass of m2=7.50×103 kg. If the two satellites collide elastically rather than dock, what is their final relative velocity?
Answer:
Their final relative velocity is 0.190 m/s
Explanation:
The relative velocity of the satellites, v = 0.190 m/s
The mass of the first satellite, m₁ = 4.00 × 10³ kg
The mass of the second satellite, m₂ = 7.50 × 10³ kg
Given that the satellites have elastic collision, we have;
[tex]v_2 = \dfrac{2 \cdot m_1}{m_1 + m_2} \cdot u_1 - \dfrac{m_1 - m_2}{m_1 + m_2} \cdot u_2[/tex]
[tex]v_2 = \dfrac{ m_1 - m_2}{m_1 + m_2} \cdot u_1 + \dfrac{2 \cdot m_2}{m_1 + m_2} \cdot u_2[/tex]
Given that the initial velocities are equal in magnitude, we have;
u₁ = u₂ = v/2
u₁ = u₂ = 0.190 m/s/2 = 0.095 m/s
v₁ and v₂ = The final velocities of the satellites
We get;
[tex]v_1 = \dfrac{2 \times 4.0 \times 10^3}{4.0 \times 10^3 + 7.50 \times 10^3} \times 0.095 - \dfrac{4.0 \times 10^3- 7.50\times 10^3}{4.0 \times 10^3+ 7.50\times 10^3} \times 0.095 = 0.095[/tex]
[tex]v_2 = \dfrac{ 4.0 \times 10^3 - 7.50\times 10^3}{4.0 \times 10^3 + 7.50 \times 10^3} \times 0.095 + \dfrac{2 \times 7.50\times 10^3}{4.0 \times 10^3+ 7.50\times 10^3} \times 0.095 = 0.095[/tex]
The final relative velocity of the satellite, [tex]v_f[/tex] = v₁ + v₂
∴ [tex]v_f[/tex] = 0.095 + 0.095 = 0.190
The final relative velocity of the satellite, [tex]v_f[/tex] = 0.190 m/s
what ia measurement in science?
= The process of comparing an unknown quantities with an standard known quantities is called measurement.
Yes it is the measurement in science
is noise energy a kind of energy or not
If you could travel 900 meters in 55 seconds, what is your speed?
(Answer in details=brainliest)
Answer:
The rate of change of distance is called speed it can also be defined as distance travelled per unit time,from these definition you can tell that the formula will be
speed=distance/time
in this question the distance is 900meters and the time is 55seconds therefore the speed will be:
s=900meters/55seconds
=16.36m/s
I hope this helps
standard unit definition
Answer:
Standard units are the units we usually use to measure the weight, length or capacity of objects.
Answer:
THE SYSTEM OF UNITS WHICH IS AGREED BY THE INTERNATIONAL CONVENTION OF SCIENTISTS HELD IN FRANCE IN 1960 IS CALLED SI SYSTEM.
A flat, circular, copper loop of radius r is at rest in a uniform magnetic field of magnitude B that extends far beyond the edge of the loop. The plane of the loop is parallel to the page and the magnetic field is directed perpendicular to and out of the page, as indicated by the blue dots. If the magnitude of the magnetic field is decreased at a rate of 1 T/s, what is true about the induced current in the copper loop
Answer:
i =[tex]- \frac{r \ A'}{2 \ rho}[/tex] , i = 0.92 A
Explanation:
This exercise asks for the electromotive force, which can be calculated with Faraday's law
fem = [tex]- \frac{d \Phi_B }{dt}[/tex]
where the magnetic flux
Ф = B. A
bold letters indicate vectors. We can write this equation
Ф = B A cos θ
In this case the magnetic field is perpendicular to the page and the normal to the loop of the loop is also parallel to the page, therefore the angle is zero and the cosine is 1
the loop is
A = π r²
we substitute in the first equation
fem = - π r² [tex]\frac{dB}{dt}[/tex]
we substitute the values
fem = -π r² 1
fem = - π r²
to calculate the current let's use ohm's law
V = i R
R = ρ L / A'
where A 'is the area of the wire and L is the length of the loop
L = 2π r
V = i (ρ 2π r / A ')
I = [tex]\frac{V \ A'}{2\pi \ r \ rho}[/tex]
In this case
V = fem
I = fem / R
i =[tex]- \frac{r \ A'}{2 \ rho}[/tex]
In order to complete the calculation, you need the radius of the loop and / or the wire cutter.
if we assume that the loop has a radius of r = 1 cm = 0.01 m and an area of the wire A'= π 10⁻⁶ m² a radius of the wire 1 mm
i = - 10⁻² π 10⁻⁶ / ( 2 1.7 10-8)
i = 0.92 A
A long distance runner running a 5km track is pacing himself by running 4.5km/h at 9km/h and the rest at 12.5km/h9
Complete Question:
A long distance runner running a 5.0km track is pacing himself by running 4.5km at 9.0km/hr and the rest at 12.5km/hr. What is the average speed?
Answer:
Average speed = 9.7333 km/h
Explanation:
Let the total distance be divided into A and B.Given the following data;
Total distance = 5 kmDistance A = 4.5 kmSpeed A = 9.5 km/hrSpeed B = 12.5 km/hrTo find the average speed;
First of all, we would determine the time taken to cover distance A in speed A by using the formula;
[tex] Time \ A = \frac {Distance \; A}{Speed \; A} [/tex]
Substituting the values into the formula, we have;
[tex] Time \ A = \frac {4.5}{9.5} [/tex]
Time A = 0.4737 hours
Total distance = distance A + distance B
5 = 4.5 + distance B
Distance B = 5 - 4.5
Distance B = 0.5 Km
Next, we would determine the time to cover distance B in speed B;
[tex] Time \ B = \frac {0.5}{12.5} [/tex]
Time A = 0.04 hours
Total time = time A + time B
Total time = 0.4737 + 0.04
Total time = 0.5137 hours
Now, we would solve for the average speed;
Mathematically, the average speed of an object is given by the formula;
[tex] Average \; speed = \frac {total \; distance}{total \; time} [/tex]
[tex] Average \; speed = \frac {5}{0.5137} [/tex]
Average speed = 9.7333 km/h
Vector A has magnitude of 8units and makes an angle of 45° with the positive x-axis. Vector B also has the same magnitude of 8units and directed along the negative x-axis. Find a. The magnitude and direction of A+B b. The magnitude and direction of A-B
Answer:
Explanation:
Because vectors have direction and x and y components you can't just add them and say that their length is 16 because A is 8 units and so is B. What you're actually finding is the magnitude and direction of the vector that results from this addition. The magnitude is the length of the resultant vector, which comes from the x and y components of A and B, and the direction is the angle between the resultant vector and the positive x axis. To add the vectors, then, we need to find the x and y components of each. We'll do the x components of A and B first so we can add them to get the x component of C. Since x values are directly related to cos, the formula to find the x components of vectors is
[tex]V_x=Vcos\theta[/tex] which is the magnitude of the vector (its length) and the angle. Finding the x components of A:
[tex]A_x=8.0cos45[/tex] so
[tex]A_x=5.7[/tex] and for B:
[tex]B_x=8.0cos180[/tex] since the negative x axis is the 180 degree axis and
[tex]B_x=-8.0[/tex] If we add them, we get
[tex]C_x=-2.3[/tex]
Now onto the y components. The formula for that is almost the same as the x components except use sin instead of cos:
[tex]A_y=8.0sin45[/tex] so
[tex]A_y=5.7[/tex] and
[tex]B_y=8.0sin180[/tex] so
[tex]B_y=0[/tex] If we add them, we get
[tex]C_y=5.7[/tex]
Now for the final magnitude:
[tex]C_{mag}=\sqrt{(-2.3)^2+(5.7)^2}[/tex] and
[tex]C_{mag}=6.1 units[/tex] and now onto the direction.
The x component of C is positive and the y component is negative, which means that the direction has us at an angle is quadrant 2; we add 180 to whatever the angle is. Finding the angle:
[tex]tan^{-1}(\frac{C_y}{C_x})=(\frac{5.7}{-2.3})[/tex] = -68 + 180 = 112 degrees
The resultant vector of A + B has a magnitude of 6.1 and a direction of 112°
Do the same thing for subtraction, except if you're subtracting B from A, the direction that B is pointing has to go the opposite way. That means that A doesn't change anything at all, but B is now pointing towards 0.
[tex]A_x=5.7[/tex] (doesn't change from above)
[tex]B_x=8.0cos0[/tex] and
[tex]B_x=8.0[/tex] so
[tex]C_x=13.7[/tex] and
[tex]A_y=5.7[/tex] (also doesn't change from above)
[tex]B_y=8.0sin0[/tex] so
[tex]B_y=0[/tex] and
[tex]C_y=5.7[/tex] and for the magnitude:
[tex]C_{mag}=\sqrt{(13.7)^2+(5.7)^2[/tex] so
[tex]C_{mag}=15units[/tex] and for the direction:
[tex]tan^{-1}(\frac{5.7}{13.7})=23[/tex] and since both x and y components of C are in Q1, we add nothing.
And you're done!!!
You're driving down the highway late one night at 20 m/s when a deer steps onto the road 35 m in front of you. You reaction time before stepping on the brakes is 0.50 s, and the maximum deceleration of your car is 10 \mathrm { m } / \mathrm { s } ^ { 2 }10m/s 2 . a. How much distance is between you and the deer when you come to a stop
Answer:
Explanation:
Discount the time here; it's not important. It doesn't tell you how long it takes the car to stop, it only refers to reaction time, which means nothing in the scheme of things.
The useful info is as follows:
initial velocity = 20 m/s
final velocity = 0 m/s
a = -10 m/s/s
and we are looking for the displacement. Use the following equation:
[tex]v^2=v_0^2+2a[/tex]Δx
where v is the final velocity, v₀ is the initial velocity, a is the deceleration (since it's negative), and Δx is displacement. Filling in:
[tex]0^2=(20)^2+2(-10)[/tex]Δx and
0 = 400 - 20Δx and
-400 = -20Δx so
Δ = 20 meters
Joule is equal to:
Awatt x metre
B.watt x second
C. Newton x Metre
D. Both b and c
Answer:
The answer is ( D) i. e both b and c.
Q: Riri wants to bake a cake. She adds flour, sugar, egg, baking soda, and yeast into a bowl and mixed them together. After all the ingredients are mixed, she leaves the dough for 30 minutes and the dough starts to rise. Which changes Occurred in this process? Explain your reason.
Answer:
I don't know what you mean about which changes occurred in this process but if its why the dough starts rising then its caused by the carbon dioxide in baking soda and yeast which is a fungus
Answer:
When baking,flour is mixed with water,the other ingredients and yeast to form a paste called a dough.what happens is that the zymase enzyme from the yeast acts on the sugars to form carbon dioxide and alcohol.the carbon dioxide begins to form bubbles in the dough causing it to rise..
I hope this helps
(b) The power rating of an electrical appliance at 750watt,calculate consumed for using the appliance for 1 hour.
Answer:
750 w : time = 1hour
Explanation:
750x1hour
=750 watt-hours
What is concave mirror?
Answer:
A concave mirror, or converging mirror, has a reflecting surface that is recessed inward (away from the incident light). Concave mirrors reflect light inward to one focal point. They are used to focus light.
Which of the following is true of highly conductive elements?
Answer:
A
Explanation:
i think a is the answer because if you take an example of group 1 and 2 metals on the periodic table you will notice that they are highly reactive but they have a few electrons in their outer most shells.
I hope this helps
Please help!! :)
For this circuit, what will be the voltage drop across R1?
A. 21.3 V
B. 14.2 V
C. 45.0 V
D. 9.47 V
Answer:
Option D. 9.47 V
Explanation:
We'll begin by calculating the equivalent resistance of the circuit. This can be obtained as follow:
Resistor 1 (R₁) = 20 Ω
Resistor 2 (R₂) = 30 Ω
Resistor 3 (R₃) = 45 Ω
Equivalent Resistance (R) =?
R = R₁ + R₂ + R₃ (series connections)
R = 20 + 30 + 45
R = 95 Ω
Next, we shall determine the current in the circuit. This can be obtained as follow:
Voltage (V) = 45 V
Equivalent Resistance (R) = 95 Ω
Current (I) =?
V = IR
45 = I × 95
Divide both side by 95
I = 45 / 95
I = 0.4737 A
Finally, we shall determine, the voltage across R₁. This can be obtained as follow:
NOTE: Since the resistors are in series connection, the same current will pass through them.
Current (I) = 0.4737 A
Resistor 1 (R₁) = 20 Ω
Voltage 1 (V₁) =?
V₁ = IR₁
V₁ = 0.4737 × 20
V₁ = 9.47 V
Therefore, the voltage across R₁ is 9.47 V.
Answer:
9.47
Explanation:
Just Took the Test
Using your Periodic Table, which of the elements below is most likely to be a solid at room temperature?
A.) potassium, B.) Hydrogen, C.) Neon, D.) Chlorine
The answer is definitely Potassium
state one similarity and one difference of sound of frequency 750Hz and ultrasound
Explanation:
Ultrasound refers to sound waves having frequencies greater than the frequency range limit. Ultrasound has the same physical qualities as "regular" (audible) music, except that individuals cannot hear it. Ultrasound devices use frequencies ranging from 20 kHz to a few gigahertz.
The frequencies of ultrasound utilised in clinical settings are generally between 2 and 12 MHz. Shorter wavelengths have a larger penetration depth into the body but less resolution; longer wavelengths have a greater depth of penetration but have a restricted depth of penetration.
Why does the Earth exert a gravitational force on objects on its surface?
A. It has an atmosphere,
B. It has mass
C. It has a magnetic field.
D. It is so dense.
Answer:
B. It has mass
Explanation:
The Newtons Universal gravitacion law is : F = G.[tex]\frac{m1 m2}{d^{2} }[/tex] , where F is the force exerted , m1 and m2 are the earth's mass and the object's mass, d is the distance and G the gravitacional constant. Comparing to the options we can say that the Earth exerts a gravitational force on objects on its surface because of its mass.
A comet of mass 2 × 10^8 kg is pulled toward the star. If the comet's initial velocity is very small, and the comet starts moving toward the star from 700,000,000 km away, how fast is it going right before it hits the surface of the star? (Assume that it does not lose any mass by melting as it approaches the star.)
Answer:
The speed of the comet at the surface of the star is approximately 1,208,694.7 m/s
Explanation:
Question parameter obtained online; The mass of the star, M = 5 × 10³¹ kg
Explanation;
The given mass of the comet, m = 2 × 10⁸ kg
The initial velocity of the comet, v → 0
The distance of the comet from the star, d = 700,000,000 km
The gravitational potential at d = G·M·m/d
The kinetic energy of the comet, K.E. = m·v²/2
The kinetic energy of the comet at d = m·(0)²/2 = 0
The gravitational potential at the surface of the star, R = G·M·m/R
The kinetic energy of the comet at the surface of the star, R = m·(v)²/2 = 0
Where;
M = The mass of the star = 5 × 10³¹ kg
[tex]M_{Sun}[/tex] = The mass of the Sun = 1.989 × 10³⁰ kg
M/[tex]M_{Sun}[/tex] = 5 × 10³¹/(1.989 × 10³⁰) ≈ 25
G = The universal gravitational constant = 6.67430 × 10⁻¹¹ N·m²/kg²
R = The radius of the star
Therefore, we have;
m·(0)²/2 - G·M·m/d = m·v²/2 - G·M·m/R
∴ v = √((G·M·m/R - G·M·m/d)×2/m) = √(2·G·M(1/R - 1/d))
Therefore; v = (2 × 6.67430 × 10⁻¹¹ × 5 × 10³¹ × (1/R - 1/700,000,000,000))
v = 81696389149.1×√(1/R - 1/700,000,000,000).
The speed of the comet at the surface of the star, v = 81696389149.1×√(1/R - 1/700,000,000,000)
The mass radius relationship is given as follows;
[tex]\dfrac{R}{R_{Sun}} = 1.30 \times \left(\dfrac{M}{M_{Sun}} \right)^{\dfrac{1}{2} }[/tex]
[tex]R = R_{Sun} \times 1.30 \times \left(\dfrac{M}{M_{Sun}} \right)^{\dfrac{1}{2} }[/tex]
The radius of the Sun = 696,340,000 M
∴ R ≈ 696,340,000 × 1.3 × √(25.14) = 4538865694.76
R = 4538865694.76 m
v = 81696389149.1×√(1/4538865694.76 - 1/700,000,000,000) ≈ 1208694.7 m/s
The question is given in the picture below.... please help me and mention all the steps..
Answer:
a)water is turning into ice it is changing it's state from liquid to solid
b)B to C ice is melting and it is changing it's state from solid to liquid
C to D water is boiling and it is changing it's state from liquid to vapours(steam)
c) temperature
At A 0
At B 0
At C 100
At D 100
Explanation: The temperature will remain 0 degrees Celsius until all the ice becomes water and the temperature will remain 100 degrees Celsius until all the water changes into steam.
An object is thrown from the ground with an initial velocity of 30 m/s. What is the velocity at the point 25 m above the ground?
Answer:
It's a pretty simple suvat linear projectile motion question, using the following equation and plugging in your values it's a pretty trivial calculation.
V^2=U^2+2*a*x
V=0 (as it is at max height)
U=30ms^-1 (initial speed)
a=-g /-9.8ms^-2 (as it is moving against gravity)
x is the variable you want to calculate (height)
0=30^2+2*(-9.8)*x
x=-30^2/2*-9.8
x=45.92m
Answer:
35
Explanation:
dfddffffffffffffdddfr
A ball is thrown vertically upward.It's velocity at the highest point is?
A. 10 ms^-1
B. Zero
C. 10 ms^-2
D. None of these
B
Explanation:
BECAUSE IT WAS GOING UPWORD THEN IT'S VELOCITY WAS DECREASING -10MS¹
Answer:
Explanation:
From physics, which is directly related to math (especially when it comes to parabolic motion!), we learn that at the very top of the parabola the object has to stop for a millisecond so it can turn around and fall back to earth. This translates to a velocity of 0 at its highest point. So B.
For problems 2-3, a Ferrari accelerates from 0-60.0 miles per hour in 2.50 seconds.
2. What is its final speed, in m/s?
a 5.6 m/s
b. 13 m/s
c. 26.8 m/s
d. 1608 m/s
0-60.0 per near
2.50 seconds
3. What is its average acceleration?
a. 24.0 m/s
b. 10.7 m/s2
c. 38.6 m/s2
d. 13 m/s
Answer:
Explanation:
The first part of this question is simply asking us to convert the speed from miles per hour to meters per second:
[tex]60.0\frac{mi}{hr}*\frac{1hr}{3600sec}*\frac{1609.34m}{1mi}=26.8\frac{m}{s}[/tex] choice C.
The next part wants us to use the equation for acceleration and find the acceleration:
[tex]a=\frac{v-v_0}{t}[/tex] where v is final velocity, v0 is initial velocity, and t is time in seconds (which was one of the reasons we had to convert the initial velocity from 60.0 mph to m/s):
[tex]a=\frac{26.8-0}{2.5}[/tex] and
a = 10.7 m/s/s, choice B.
En un rio una Onda viaja con una velocidad de propagación de 50 m/s con una longitud de Onda de 40 metros. Hallar la frecuencia de la Onda.
Answer:
Frequencia = 1.25 Hz
Explanation:
Dados los siguientes datos;
Velocidad = 50 m/s Longitud de onda = 40 metrosPara encontrar la frecuencia de la onda;
Matemáticamente, la velocidad de una onda viene dada por la fórmula;
[tex] Velocidad = Longitud \; de \; onda * Frequencia [/tex]
Haciendo de la frecuencia el tema de la fórmula, tenemos;
[tex] Frequencia = \frac {Velocidad}{Longitud \; de \; onda} [/tex]
Sustituyendo en la fórmula, tenemos;
[tex] Frequencia = \frac {50}{40} [/tex]
Frequencia = 1.25 Hz
Can I answer my own question
Answer:
Well okay do it what's your question ?
Answer:
yes
Explanation:
Which of the following is occurring while a satellite is in orbit around Earth? O It is continuously pulling away from Earth It is continuously falling toward the surface of Earth. It stays in a constant speed orbit where it was oriented from the start. It stays in the same orbit orientation traveling at variable speeds.
AnswerIt is continuously falling towards the surface of the earth
Explanation:
since gravity from earth is the thing that keeps it constantly in orbit
The electrical resistance of an element in a platinum resistance thermometer at 100°c, 0°c and room temperature are 75.00Ω, 63.00Ω and 64.992Ω respectively. Use the data to calculate room temperature
Answer:
16.6 °C
Explanation:
From the question given above, the following data were obtained:
Temperature at upper fixed point (Tᵤ) = 100 °C
Resistance at upper fixed point (Rᵤ) = 75 Ω
Temperature at lower fixed point (Tₗ) = 0 °C
Resistance at lower fixed point (Rₗ) = 63.00Ω
Resistance at room temperature (R) = 64.992 Ω
Room temperature (T) =?
T – Tₗ / Tᵤ – Tₗ = R – Rₗ / Rᵤ – Rₗ
T – 0 / 100 – 0 = 64.992 – 63 / 75 – 63
T / 100 = 1.992 / 12
Cross multiply
T × 12 = 100 × 1.992
T × 12 = 199.2
Divide both side by 12
T = 199.2 / 12
T = 16.6 °C
Thus, the room temperature is 16.6 °C
