Answer:
C. Diffraction
Explanation:
Diffraction is the bending of waves as they pass by a barrier or through an opening. One of the condition for diffraction is that the size of the aperture or obstacle is comparable to the wavelength of light. Fresnel diffraction and Fraunhofer diffraction are two types of diffraction.
Hence, the correct option is (c) "Diffraction".
A world-class tennis player can serve a tennis ball at 130 mi/h mi/h (about 58 m/s m/s ). The length of a tennis court is 78 ft ft . Approximately how long does an opponent have to react from the instant the ball is served until the ball reaches the opponent?.
Answer:
The time taken is [tex]t = 0.4103 \ s[/tex]
Explanation:
From the question we are told that
The speed is [tex]v = 130 \ mi/h = 58 \ m/s[/tex]
The length of the tennis court [tex]l = 78 \ ft = \frac{78}{3.281}= 23.8 \ m[/tex]
Generally the time taken is mathematically represented as
[tex]t = \frac{ 23.8}{ 58}[/tex]
=> [tex]t = 0.4103 \ s[/tex]
The electric field is strongest where equipotential curves are:_______.A) closest togetherB) farthest apartC) most nearly straightD) most curvy
Answer:
A closest
Explanation:
This is because the electric field will be strongest or largestwhen the equipotential curves are closest together
We know that the field is
E= V/d
Where is distance and we see that d being the denominator will only make E bigger if it becomes smaller that is the curves closest
Which of the following best describes how to calculate the average acceleration of any object?
a. Average acceleration is always halfway between the initial acceleration of an object and its final acceleration.
b. Average acceleration is always equal to the displacement of an object divided by the time interval.
c. Average acceleration is always equal to the change in velocity of an object divided by the time interval.
d. Average acceleration is always equal to the change in speed of an object divided by the time interval.
Answer:
c)Average acceleration is always equal to the change in velocity of an object divided by the time interval.
Explanation:
Because average acceleration= a2+a1/2
Which is equal to change in velocity which is a time rate of change of velocity v-u/t which actually explains average acceleration
How many coulombs of positive charge (in units of 107 C) are there 1.53 kg of plutonium, given its atomic mass is 244 and that each plutonium atom has 94 protons? 1 atomic mass unit = 1.66*10-27 kg Enter a number with two digits behind the decimal point.
Answer:
The value is [tex]q = 5.72 *10^7 \ C[/tex]
Explanation:
From the question we are told that
the mass is [tex]m = 1.53 \ kg[/tex]
The atomic mass is [tex]u = 244 g/mol = 0.244 kg/mol[/tex]
The number of protons on each atom is [tex]N = 94 \ protons[/tex]
The mass of one atomic mass unit is [tex]M = 1.66 *10^{-27} \ kg[/tex]
Generally the number of atoms present is
[tex]k = \frac{m * N_a }{u}[/tex]
Here [tex]N_a[/tex] is the Avogadro constant with value [tex]N_a = 6.023 *10^{23} \ atoms /mol[/tex]
=> [tex]k = \frac{1.53 * 6.023*10^{23}}{ 0.244}[/tex]
=> [tex]k = 3.8 *10^{24} \ atoms[/tex]
The coulombs of positive charge on the plutonium is mathematically represented as
[tex]q = k * N * e[/tex]
Here e is the charge on a proton with value [tex]e = 1.60 *10^{-19}\ C[/tex]
[tex]q = 3.8 *10^{24} * 94 * 1.60*10^{-19}[/tex]
[tex]q = 5.72 *10^7 \ C[/tex]
Sympathy, Unproductive, Perspectives
Empathetic people try to look at things from different _______
People with low empathy often are unable to understand others perspective and involve in _____arguments.
_________ is when you feel sorry for the other person and there is no urge, no impelling reason to be feel others feelings.
Answer:
Empathetic people try to look at things from different perspectives
People with low empathy often are unable to understand others perspective and involve in unproductive arguments.
sympathy is when you feel sorry for the other person and there is no urge, no impelling reason to be feel others feelings.
Explanation:
What is the opposite of yummy??? PLEASE I GIVE BRainlIEST NO NOOBS PLZZ
Answer:
tasteless
Explanation:
Find the height or length of these natural wonders in km, m, and cm.A. A cave system with a mapped length of 354 miles.B. A waterfall that drops 1,235.2 ft.C. A 21320 ft tall mountain.
D. A canyon with a depth of 6630 ft.
Explanation:
Some standard unit conversion are 1 mile = 1.609344 km, 1 ft.= 30.48 cm,
1 km= 1000 m or 1 m = 0.001 km and 1 m= 100 cm or 1 cm=0.01 m.
Now, use these values to convert the given lengths.
A. length of cave = 5 miles (given)
From standard value 1 mile = 1.609344 km
[tex]\Rightarrow[/tex] 5 miles = [tex]\times[/tex] 1.609344 km= 8.04672 km,
[tex]\Rightarrow[/tex] 5 miles =8.04672 [tex]\times[/tex] 1000 m= 8046.72 m [ as 1 km = 1000 m]
[tex]\Rightarrow[/tex] 5 miles = 8046.72 [tex]\times[/tex] 100 cm=804672 cm
B. Height of the waterfall = 1235 ft. (given)
1 ft.= 30.48 cm [ from standard value]
[tex]\Rightarrow[/tex] 1235.2 ft.= 1235.2[tex]\times[/tex] 30.48 cm=37648.896 cm,
[tex]\Rightarrow[/tex] 1235.2 ft.=37648.896 [tex]\times[/tex] 0.01 m =376.48896 m [ as 1 cm = 0.01 m]
[tex]\Rightarrow[/tex] 1235.2 ft.=376.48896 [tex]\times[/tex] 0.001 km =0.37648896 km [ as 1 m = 0.001 km]
C. Height of the mountain= 21320 ft. (given)
From standard value: 1 ft.= 30.48 cm
[tex]\Rightarrow[/tex] 21320 ft.= 21320 [tex]\times[/tex] 30.48 cm=649833.6 cm,
[tex]\Rightarrow[/tex] 21320 ft.=649833.6 [tex]\times[/tex] 0.01 m =6498.336 m [ as 1 cm = 0.01 m]
[tex]\Rightarrow[/tex] 21320 ft.=6498.336 [tex]\times[/tex] 0.001 km =6.498336 km [ as 1 m = 0.001 km].
D. Depth of canyon =6630 ft.
From standard value: 1 ft.= 30.48 cm
[tex]\Rightarrow[/tex] 6630 ft.= 6630 [tex]\times[/tex] 30.48 cm=202082.4 cm,
[tex]\Rightarrow[/tex] 6630 ft.=202082.4 [tex]\times[/tex] 0.01 m =2020.824 m [ as 1 cm = 0.01 m]
[tex]\Rightarrow[/tex] 6630 ft.=2020.824 [tex]\times[/tex] 0.001 km =2.020824 km [ as 1 m = 0.001 km].
Carbohydrates are the main building block of tissues and organs. True False
That statement is false.
Proteins are.
Answer:
That statement is false.
Proteins are.
Explanation:
Question 4 of 10
Which option is part of designing a set of experimental procedures?
O A. Developing a hypothesis
B. Determining how data will be gathered
C. Submitting conclusions to the peer-review process
O D. Beginning to take measurements
Answer:
Determining how data will be gathered
Explanation:
As a scientist considers the use of a particular set of experimental procedures to carry out his research, an important consideration is the method of data collection.
The experimental procedures chosen must be those that make the process of data collection much easier, efficient and lead to collection of reliable data.
Hence determining the method of data collection is very important when designing a set of experimental procedures.
4. Describe how the velocity of an object changes if it undergoes uniformly acceleration motion. Can its direction change?
Answer:
n the case of linear motion, the change occurs in the magnitude of the velocity, the direction remaining constant.
In the case of circular motion, the magnitude of the velocity remains constant, the change in its direction occurring.
Explanation:
Velocity is a vector therefore it has magnitude and direction, a change in either of the two is the consequence of an acceleration on the system.
In the case of linear motion, the change occurs in the magnitude of the velocity, the direction remaining constant.
[tex]a_{t}[/tex] = (v₂-v₁)/Δt
In the case of circular motion, the magnitude of the velocity remains constant, the change in its direction occurring.
[tex]a_{c}[/tex] = v2/R
In the general case, both the module and the address change
a = Ra ( a_{t}^2 + a_{c}^2)
The velocity of an object changes if it undergoes uniformly acceleration
motion by considering if it is:
Positive constant accelerationNegative constant accelerationWhat is Velocity?This is the rate of change of an object's position with time. If the object has
positive constant acceleration, the slope goes upward while if it is a
negative constant acceleration, the slope goes downward.
The direction doesn't change as a result of the uniform speed and
direction that is involved.
Read more about Velocity here https://brainly.com/question/6504879
what best describes the bromide ion that forms
Answer:
it A
Explanation:
Its a negative ion that hss one less valence electron than a netural bromine atom
A major contribution of Johannes Kepler to the development of modern astronomy was:________.
Answer:
The answer is planetary motionExplanation:
According to Johannes Kepler, the laws governing planetary motion
states that:
1. The orbit of a planet is an ellipse with the Sun at one of the two foci.
2. A line segment joining a planet and the Sun sweeps out equal areas
during equal intervals of time.
3. The square of a planet's orbital period is proportional to the cube of the semi-major of its orbit.
Johannes Kepler was a German astronomer, mathematician, and astrologer
Born: 27 December 1571, Weil der Stadt, Germany
Died: 15 November 1630
When you do work on an object some of the energy is ___ to that object
Answer:
The answer is transferred. So your answer will be: When you do work on an object some of the energy is transferred to that object.
A string has mass 5.0 grams, and is stretched with 180 N of tension. A wave travels on this string with frequency 260 Hz and wavelength 0.60 m. Determine the length of the string.
Answer:
3.68×10¯⁶ m
Explanation:
The following data were obtained from the question:
Mass (m) = 5 g
Tension (T) = 180 N
Frequency (f) = 260 Hz
Wavelength (λ) = 0.60 m.
Length (L) =?
Next, we shall determine the period of the wave. This can be obtained as follow:
Period is simply defined as the time taken to complete 1 oscillation. Mathematically, it is represented as:
Period (T) = 1/frequency (f)
T = 1/f
Thus, with the above formula, the period of the wave can be obtained as shown below:
Frequency (f) = 260 Hz
Period (T) =?
T = 1/f
T = 1/260
T = 3.85×10¯³ s
Finally, we shall determine the length of the string as follow:
Period (T) = 3.85×10¯³ s
Acceleration due to gravity (g) = 9.8 m/s²
Pi (π) = 3.14
Length (L) =?
T = 2π√(L/g)
3.85×10¯³ = 2 × 3.14 × √(L/9.8)
3.85×10¯³ = 6.28 × √(L/9.8)
Divide both side by 6.28
3.85×10¯³ / 6.28 = √(L/9.8)
Take the square of both side
(3.85×10¯³ / 6.28)² = L/9.8
Cross multiply
L = (3.85×10¯³ / 6.28)² × 9.8
L = 3.68×10¯⁶ m
Therefore, the length of the string is 3.68×10¯⁶ m
Barney walks 6 steps north, 4 steps to the west, 2 more steps north, and 10 more steps to the west. What is Barney's
displacement?
The magnitude of total displacement of Barney is 16.12 meters in an angle 29.75 ° with north in north east direction..
What is displacement?The term "displacement" refers to a shift in an object's position. It is a vector quantity with a magnitude and direction. The symbol for it is an arrow pointing from the initial location to the ending place.
Given parameters:
Barney walks 6 steps north, 4 steps to the west, 2 more steps north, and 10 more steps to the west.
He walks = ( 6+2)steps towards north.
= 8 steps towards north.
He walks = ( 4 + 10 ) steps to the west
= 14 steps to the west.
The magnitude of his total displacement = √(8² + 14²) meters = 16.12 meters.
And the direction is = tan⁻¹(8/14) north east. = 29.75 ° with north in north east direction.
Hence, the magnitude of total displacement of Barney is 16.12 meters in an angle 29.75 ° with north in north east direction..
Learn more about displacement here:
https://brainly.com/question/11934397
#SPJ2
if an object is not accelerating, then one knows for sure that it is_____.
) Un círculo de 120 cm de radio gira a 600 rpm. Calcula: a) su velocidad angular
b) su velocidad lineal en la llanta
c) su periodo
d) su frecuencia
Responder:
20πrads ^ -1; 24πrads ^ -1; 0,1 seg; 10 Hz
Explicación:
Dado lo siguiente:
Radio (r) del círculo = 120 cm
600 revoluciones por minuto en radianes por segundo
(600 / min) * (2π rad / 1 rev) * (1min / 60seg)
(1200πrad / 60sec) = 20π rad ^ -1
Velocidad angular (w) = 20πrads ^ -1
Velocidad lineal = radio (r) * velocidad angular (w)
Velocidad lineal = (120/100) * 20πrad
Velocidad lineal = 1.2 * 20πrads ^ -1 = 24πrads ^ -1
C.) Período (T):
T = 2π / w = 2π / 20π = 0.1 seg
D.) Frecuencia (f):
f = 1 / T = 1 / 0.1
1 / 0,1 = 10 Hz
Assume the density of the sea water is 1.024x103 kg/m3 and the pressure at sea surface is 1.01x105 Pa. What is the total pressure at an ocean depth of 700 m.
Explanation:
imagine a column of water of 1 m² that starts at the surface of the ocean, which goes straight down 700m.
You need to calculate the pressure induced by only the column of water.
Please understand that the total pressure is found by adding the pressure of the column of water AND that of the pressure of the atmosphere.
p = F/A
p = pressure in Pa
F = Force in N
A = area in m²
To calculate the Force that gravity has on that column of water, you simply use:
F = m * g
where g = 9.81 kgm/s²
So first you need to calculate the mass of the column sea water with a density of 1.024*10³ kg/m³
Tony completed a 720 km journey with an average speed of
90 km/h. For the first 285 km, he travelled at an average speed
of 95 km/h. What was the average speed for the remaining
journey?
Answer:
87 km/h
Explanation:
What feature of the sun is a section that is cooler than its surroundings
Answer:
sunspots looking dark
A train is moving at a constant speed on a surface inclined upward at 15.0° with the horizontal and travels 300 meters in 5 seconds. Calculate the horizontal velocity of the train at the end of 3 seconds.
Answer:
57,9 m/s
Explanation:
A train is moving at a constant speed on a surface inclined upward at 15.0° with the horizontal and travels 300 meters in 5 seconds. The horizontal velocity of the train at the end of 3 seconds is 100m/s.
The first formula we will use is:
v = d/t
300m ÷ 5s = 60m/s
The last formula we will use is:
vh = v·cosx
60m/s·cos15.0°
60m/s · 0,965 = 57,9 m/s
Therefore, the answer is 57,9 m/s.
Hope this helped!
57,9 m/s
Explanation:velocity formula
v = d/t
= 300m/5s
= 60m/s
horizontal velocity formula
vh = v·cosx
= 60m/s×cos15°
= 60m/s×0,965
= 57,9 m/s
How many Joules are absorbed by a pot of water with a mass of 600 g in order to raise the temperature from 30° C to 40° C? (The specific heat of water is 4.184 J/g°C) *
Answer:
25104 J
Explanation:
We are given;
Mass; m = 600 g
Change in temperature;Δt = (40 - 30) = 10°C
Specific heat of water; c = 4.184 J/g°C
Now, to find how many joules, we simply use the formula for quantity of heat.
Thus;
Q = mcΔt
Plugging in the relevant values to give;
Q = 600 × 4.184 × 10
Q = 25104 J
Quantity of heat = 25104 J
When rubbing two insulators together, the one that gets a positive charge has had:______.a) protons added. b) protons removed. c) electrons added. d) electrons removed.
Answer:
d) electrons removed.
Explanation:
Two insulators are electrically neutral, that is, the number of electrons and protons are equal. When one insulator is rubbed against another, electrons are removed from one of the insulators due their high mobility. The insulator which lost the electrons becomes positively charged while the one that gained the electron becomes negatively charged.
Therefore, when rubbing two insulators together, the one that gets a positive charge has had electrons removed.
A machine, modeled as a simple spring-mass system, oscillates in simple harmonic motion. Its acceleration is measured to have an amplitude of 10,000 mm/s2 with a frequency of 8 Hz. Compute the maximum displacement the machine undergoes during this oscillation.
Answer:
3.96*10^-3 m
Explanation:
Given that
Amplitude, A = 10000 mm/s² = 10 m/s²
Frequency, f = 8 hz
the maximum acceleration of a simple harmonic motion is given as
|a|(max) = Aw², where
A = amplitude of the simple harmonic motion
w = angular frequency of the simple harmonic motion
Remember, w = 2πf, so
w = 2 * 3.142 * 8
w = 50.272 rad/s
Rearranging the formula, and making a the subject, we have
A = |a|(max) / w², so that
A = 10 / 50.272²
A = 10 / 2527.27
A = 0.00396 m
A = 3.96*10^-3 m
You walk out of pace of 1.38 m/s for 7 minutes, how far do you travel in meters
Answer:
7 × 60 (minute to seconds) = 420 seconds
1.38 × 420 = 579.6m
A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 3.00 m/s, and her takeoff point is 1.80 m above the pool.(a) How long are her feet in the air?(b) What is the highest point above the board her feet reach? (c) What is her velocity when her feet hit the water?
Answer:
A) 0.9844 s
B) x2 = 0.4587 m
C) v = 6.657 m/s
Explanation:
We are given;
Height of take off point above pool; x1 = 1.8 m
Initial take off velocity; u = 3 m/s
Final velocity at highest point before free fall; v = 0 m/s
B) To find the highest point above the board her feet reaches means the distance from take off to the top of the motion just before free fall.
Thus, we will be using equation of motion and we have;
v² = u² + 2gs
Now, let s = x2 which will be the distance between take off and the top before free fall.
So;
v² = u² + 2g(x2)
Now,since the motion is against gravity, g will be negative.
Thus;
v² = u² + 2(-9.81)(x2)
Plugging in the relevant values to give;
0² = 3² - (19.62x2)
19.62(x2) = 9
x2 = 9/19.62
x2 = 0.4587 m
A) We want to find how long her feet is in air.. It means we want to find out the time to get to a distance of x1 and also the time to achieve the distance (x1 + x2) on free-fall.
Thus, using equation of motion;
v = u + gt
Again, g = -9.81
Thus;
0 = 3 - 9.81t1
9.81t1 = 3
t1 = 3/9.81
t1 = 0.3058 s
Now, for the time taken to achieve the distance (x1 + x2) on free-fall, we will use the formula;
s = ut + ½gt²
Where s = (x1 + x2) = 1.8 + 0.4587 = 2.2587 m
And now, u = 0 m/s because the start of the free fall is from maximum height with velocity of 0 m/s. Again, g = - 9.81 m/s²
Thus;
2.2587 = 0 - ½(-9.81)(t2)²
2.2587 = 4.905(t2)²
(t2)² = 2.2587/4.905
(t2)² = 0.4605
t2 = √0.4605
t2 = 0.6786 s
Thus, total time of feet in air = t1 + t2 = 0.3058 + 0.6786 = 0.9844 s
C) Velocity when feet hit the water would be given by;
v = u + gt
Where u = 0 m/s and t = t2 = 0.6786
Since it's in direction of gravity, g = 9.81 m/s
v = 0 + (0.6786 × 9.81)
v = 6.657 m/s
A white blood cell has a diameter of approximately 12 micrometers or 0.012 um a model represents its diameter as 24 um what ratio of model size
Answer:
The ratio of the model size is 1 : 2000
Explanation:
Given
Real Diameter = 0.012 um
Scale Diameter = 24 um
Required
Determine the scale ratio
The scale ratio is calculated as follows;
[tex]Scale = \frac{Real\ Measurement}{Scale\ Measurement}[/tex]
Substitute values for real and scale measurements
[tex]Scale = \frac{0.012\ um}{24\ um}[/tex]
Divide the numerator and the denominator by 0012um
[tex]Scale = \frac{1}{2000}[/tex]
Represent as ratio
[tex]Scale = 1 : 2000[/tex]
Hence, the ratio of the model size is 1 : 2000
Answer:
Explanation: The Answer Is D Two Thousand & The Number
A baseball is thrown horizontally at 46 m/s. The ball slows down at a rate of 5 m/s2. How long is the ball in the air before coming to rest?
Answer:
9.2 s
Explanation:
Given:
v₀ = 46 m/s
v = 0 m/s
a = -5 m/s²
Find: t
v = at + v₀
0 m/s = (-5 m/s²) t + 46 m/s
t = 9.2 s
A marble slides along a frictionless track at a constant speed u before encountering a section of the track that is covered with a thin layer of putty. The instantaneous velocity v of the marble as it slides past the putty, as a function of time t, is given byv(t)=u-bt+ct^3where t = 0 at the moment when the marble first comes into contact with the putty. As the marble exits the region covered in putty, the marble\'s instantaneous acceleration goes to zero. For u = 2.50 m/s, b = 3.55 m/s2, and c = 6.70 m/s4, calculate the length of the track that is covered with putty._______m
Answer:
x = 78.9 cm
Explanation:
The instantaneous velocity v of the marble as it slides past the putty, as a function of time t, is given by
[tex]v(t)=u-bt+ct^3[/tex]
u = 2.50 m/s, b = 3.55 m/s², and c = 6.70 m/s⁴
As the marble exits the region covered in putty, the marble\'s instantaneous acceleration goes to zero.
[tex]a=\dfrac{dv}{dt}\\\\a=\dfrac{d(u-bt+ct^3)}{dt}\\\\a=-b+3ct^2[/tex]
or
[tex]0-3.55+3\times 6.7t^2\\\\0=-3.55+20.1t^2\\\\t=\sqrt{\dfrac{3.55}{20.1}} \\\\t=0.42\ s[/tex]
Let x is the length of the track.
[tex]v=\dfrac{dx}{dt}\\\\\text{or}\\\\\int\limits_0^x {dx} =\int\limits^{4.2}_0 {vdt} \\\\x=\int\limits^{4.2}_0 {u-bt+ct^3} \, dt\\\\x=[ut-\dfrac{bt^2}{2}+\dfrac{ct^4}{4}]_0^ {0.42}\\\\\text{Putting limits}\\\\x=0.42u-\dfrac{b(0.42)^2}{2}+\dfrac{c(0.42)^4}{4}\\\\\text{Now, put values of u,b and c}\\\\x=0.42(2.5)-\dfrac{3.55\times (0.42)^2}{2}+\dfrac{6.7\times (0.42)^4}{4}\\\\x=0.789\ m\\\\x=78.9\ cm[/tex]
So, the length of the track that is covered with putty is 78.9 cm.
The length of the track is covered with putty is 0.789 m.
How do you calculate the length of the track?The instantaneous velocity v of the marble as a function of time t is given below.
[tex]v(t)=u-bt+ct^3[/tex]
Where t = 0 at the moment when the marble first comes into contact with the putty. Also given that, u = 2.50 m/s, b = 3.55 m/s², and c = 6.70 m/s⁴.
Given that the acceleration = 0 as the marble exits the region covered in putty. The acceleration is the rate change in the velocity with respect to time.
[tex]a = \dfrac {dv}{dt}[/tex]
[tex]a = \dfrac {d(u-bt+ct^3)}{dt}[/tex]
[tex]a = -b + 3ct^2[/tex]
Substituting the values in the above equation, we get the time.
[tex]0 = -3.55 + 3 \times 6.70 t^2[/tex]
[tex]t^2 = 0.1766[/tex]
[tex]t = 0.42 \;\rm s[/tex]
Hence the time interval is t =0 to t = 0.42 seconds.
Let us consider that the length of the track is l. Then the velocity can be written as the function of length is given below.
[tex]v = \dfrac {dl}{dt}[/tex]
[tex]dl = vdt[/tex]
[tex]\int_{0}^{t}dl = \int_{0}^{0.42} vdt[/tex]
[tex]l = \int_{0}^{0.42} (u-bt+ct^3) dt[/tex]
[tex]l =[ ut-\dfrac {bt^2}{2} + \dfrac {ct^4}{4} ]_0^{0.42}[/tex]
Putting the value t = 0.42,
[tex]l = 2.50 \times 0.42 - \dfrac {3.55 \times (0.42)^2}{2} + \dfrac { 6.70 \times (0.42)^4}{4}[/tex]
[tex]l = 0.789 \;\rm m[/tex]
Hence the length of the track is covered with putty is 0.789 m.
To know more about velocity and acceleration, follow the link given below.
https://brainly.com/question/2437624.
g An astronaut must journey to a distant planet, which is 189 light-years from Earth. What speed will be necessary if the astronaut wishes to age only 12 years during the round trip? (Give your answer accurate to four decimal places.)
Answer:
The value is [tex]v = 2.999 *10^{8} \ m/s[/tex]
Explanation:
From the question we are told that
The time taken to travel to the planet from earth is [tex]t = 189 \ light-years[/tex]
The time to be spent on the ship is [tex]t_{s} = 12 \ years[/tex]
Generally speed can be obtained using the mathematical relation represented below
[tex]t_s = 2 * t * \sqrt{1 - \frac{v^2}{c^2 } }[/tex]
The 2 in the equation show that the trip is a round trip i.e going and coming back
=> [tex]12 = 2 * 189 * \sqrt{1 - \frac{v^2}{(3.0*10^{8})^2 } }[/tex]
=> [tex]v = 2.999 *10^{8} \ m/s[/tex]