Answer:
14 years
Explanation:
because the light will take four years to reach the earth. And the star is four light years away from the earth.
Hope that helps you please followAn imaginary star is four light years from earth. The star has a planet, upon which a large mirror has been installed. The mirror faces earth. A ten year old boy aims his telescope at the mirror,then the boy would be 14 years old when he will see his own reflection.
What is a light year?
It can be defined as the distance travelled by the light in one year .it is represented in units of distance such as miles or km.
1 light year is calculated by multiplying the speed of light with the time of one year
1 light year = speed of light × one year time period
1 light year = 3×10⁸ ×(365×24×60×60)
=9.461× 10¹⁵ meter
As given in the problem 10 year old boy aims his telescope at the mirror which is 4 light years away then the light has to travel four years to reach the boy ,then the boy would be 14 year old when he would see his own reflection.
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An iron weight, suspended by a string, is motionless. The tension
in the string is 4.75 newtons. What is the mass of the iron
weight?
Answer:
Explanation:
If the mass hangs at the end of the string and the string can support the mass and doesn't break, and the mass hangs still, that means that the tension in the string is equal to the downward pull of the mass. However, we are given the tension in Newtons and the mass needs to be in kg. So we use the equation for weight:
w = mg where w, the weight, is the same as the tension in the string. Gravity is always 9.8 in the metric system:
4.75 = m(9.8) so
m = .48 kg
Answer:
Answer: A
0.485 Kg
Explanation:
Which type of reactions usually happens slowest?
Answer:
option b is correct..................
Tính công của dòng điện
Answer:
CG gh sure er go b vh pxuh FPI OO c AM h kh
cho 11,2 lit hỗn hợp gồm metan và etilen tác dụng với dung dịch brom. sau phản ứng xảy ra toàn thấy có chất khí thoát ra và 40 gam brom tham gia phản ứng .
a) viết phương trình phản ứng xảy ra
b) tính thành phần phần trăm thể tích mỗi chất trong hỗn hợp
c) đốt cháy toàn bộ thể tích khí thoát ra sau đó cho chất khí thu được tác dụng với 100ml dung dịch Ca(OH)2 1,25 M. tính khối lượng chất thu được sau phản ứng . biết metan ko tác dụng với brom , các chất khí đo ở điều kiện tiêu chuẩn
A cricketer throws a ball sideways with an initial velocity of 30 m/s. She releases the ball from a height of 1.3m. Calculate how far the ball travels before hitting the ground.
Answer:
78.34
Explanation:
1.3/30=78.3m
Enlight the contribution of science and technology for current pandemic of Corona virus??
The vaccine ofcourse. They helped in making the vaccine.
Write the dimension of a / b in the x = at + bt2. Where x is the distance and t is the time?
The dimension of a/b where x is the distance and t is the time is T
Given the expression
x = at + bt²
where
x is the distance
t is the time
Based on the homogeneity principle, the expression on the left-hand side must be equal to that on the right. Hence;
x = at
[tex]a = \frac{x}{t}[/tex]
Since x is the distance and distance is measured in metres, the dimension equivalent will be the length 'L'
Since t is the time and time is measured in seconds, the dimension equivalent will be the seconds 'T'
[tex]a=\frac{L}{T}[/tex]
Similarly;
x = bt²
[tex]b=\frac{x}{t^2}\\b=\frac{L}{T^2}[/tex]
Next is to get a/b;
[tex]\frac{a}{b} = \frac{L}{T} \div \frac{L}{T^2}\\\frac{a}{b} = \frac{L}{T}*\frac{T^2}{L} \\\frac{a}{b} =\frac{T^2}{T}\\\frac{a}{b} =T[/tex]
Hence the dimension of a/b is T
what is refraction and reflection
Answer:
Reflection is simply the property of a light that rebounds or bounces back after hitting a surface.
Refraction is when the light, which passes through a surface, undergoes some changes in appearance whenever it usually passes through a medium.
A sound frequency 100Hz and wavelength 3.34m is travelling through air, calculate the Velocity of sound in air.
Answer:
334m/s
Explanation:
If you take the data you gave and insert it into the equation f=v/λ the frequency would come out to be 3.34m
334 m/s is the Velocity of sound in air.
What is the velocity of a wave?Wave velocity in common usage refers to speed, although, properly, velocity implies both speed and direction.
The velocity of a wave is equal to the product of its wavelength and frequency (number of vibrations per second) and is independent of its intensity.
Mathematically , v=fλ
According to the question,
Sound frequency (f) = 100Hz
Wavelength (λ)= 3.34m
Computing the values in the formula,
v=fλ
v = 100Hz x 3.34m
v= 334m/s
Therefore,
Velocity of sound in air is 334 m/s.
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help with this physics question please :)
Answer:
is that rm in you profile pic
Why do scientists not use US customary units when reporting their data?
One of the scientist's jobs is to report the results of his experiments to all the other scientists in the world.
There isn't a single real science shop anywhere in the world that uses the US customary system of units. Not one.
Even in the measly three countries that use it for measuring carpet, pumping gas, and weighing fish ... Myanmar, Liberia, an the USA ... the scientists do their work in the SI/MKS/metric system.
Suppose high tide is at midnight, the water level at midnight is 3 m, and the water level at low tide is 0.5 m. Assuming the next high tide will occur 12 hours later (at noon), find the time, to the nearest minute, when the water level is at 1.125 m for the second time after midnight.
We have that the time, to the nearest minute, when the water level is at 1.125 m for the second time after midnight is
[tex]t=10.0hours[/tex]
From the Question we are told that
Maximum height [tex]h_{max}=3m[/tex]
Minimum height [tex]H_{min}=0.5m[/tex]
Time for next high tide will occur[tex]T=12 hours =>720 min[/tex]
Generally Average Height
[tex]h_{avg}=\frac{3+0.5}{2}\\\\h_{avg}=1.75[/tex]
Therefore determine Amplitude to be
[tex]A=h_{max}=j_{avg}\\\\A=3-1.75\\\\A=1.25[/tex]
Generally, the equation for Time is mathematically given by
At t=0
[tex]h(x)=Acos(Bx)+h_{avg}[/tex]
Where
[tex]B=\frac{2\pi}{P}\\\\B=\frac{2\pi}{720}\\\\B=8.73*10^{-3}[/tex]
Therefore
[tex]h(t)=Acos8.73*10^{-3}(t)+h_{avg}[/tex]
Hence the Time at [tex]T=1.125[/tex] is
[tex]1.125(t)=1.25cos(8.73*10^{-3})(t)+1.75[/tex]
[tex]-0.1249t=1.75[/tex]
[tex]t=10.0hours[/tex]
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A train 90m long stops in a train station with its front buffers in line with a lamp post on the platform. Later it starts off with an average acceleration of 0.45m/s. What will be its speed in kilometers per hour when the tail buffers pass the lamp post P?
Answer:
The speed of the train when the tail buffers pass the lamp post is 9 m/s
Explanation:
The given parameters are;
The length of the train = 90 m
The initial velocity of the train, u = 0
The average acceleration of the train, a = 0.45 m/s²
When the tail buffer pass the lamp post, P, we have;
The distance travelled, s = The length of the train = 90 m
The kinematic equation of motion is given as follows;
v² = u² + 2·a·s
Where;
v = The speed of the train when the tail buffers pass the lamp post
∴ v² = 0² + 2 × 0.45 m/s² × 90 m = 81 m²/s²
Therefore;
v = √(81 m²/s²) = 9 m/s
The speed of the train when the tail buffers pass the lamp post, v = 9 m/s.
numerical filing method is more scientific why give me 4 reason
Answer:
Numerical Methods are mathematical way to solve certain problems.Whether the equations are linear or nonlinear, efficient and robust numerical methods are required to solve the system of algebraic equations.
Analytical solutions are exact solutions based on mathematical principles.
However, the governing partial differential equations of fluid flow are complex and cannot be solved by analytical means. The partial differential equations are therefore converted into a system of algebraic equations that are subsequently solved through numerical methods to provide approximate solutions to the governing equations.
Although we rarely reach on exact answer , we can get really close to the exact answer much quicker than solve analytically.
Answer:
oh my god
Explanation:
how long answer is this
Ans it fastly
i need the ans fastly
NO SPAM
12. C
13. A
14. B
15. D
16. D
17. B
The radius of the base of a wooden cylinder 2m and its altitude is 7m. What is its mass?
Answer:
88 m ^2
Explanation:
what is momentum
what is momentum in words
Answer:
It's a strength or force
Explanation:
the quantity of motion of a moving body, measured as a product of its mass and velocity
Answer:
momentum is a quality define as the product of the mass and velocity of an object.
A ferrari has a mass of 1485kg.what is it's weight on Earth
F = m · g
m = 1485 kg
g = 10 N/kg
F = 1485 kg · 10 N/kg = 14 850 N = 14,85 kN
Answer: The weight on Earth is 14,85 kN.
Write down the role played by four digestive juices in digestion and the
organs which secrete them.
Answer:
Digestive juices secreted by various organs such as salivary glands in the mouth, stomach, liver and pancreas help in the process of digestion of food. Saliva secreted by the salivary glands in the mouth aids in the breakdown of starch present in the food to simple sugar
Explanation:
6.
For a given prism the angle of incidence is changed from 0° and 90', the angle of deviation [ ]
b) decreases
c) first decreases and then increases
d) first increases and then decreases
a) increases
Answer:
increase
Explanation:
please mark as brainlyest
Answer
A.Increses
Explanation:
Why do scientists not use US customary units when reporting their data?
An object moving north with an initial velocity of 14 m/s accelerates 5 m/s2 for 20 seconds. What is the final velocity of the object?
39 m/s
90 m/s
114 m/s
414 m/s
Answer:
option C
Explanation:
Final velocity of the object is 114 m / s. Hence, final velocity of the object is 114 m / s.
State any ten reasons why students in Uganda need to study physics?use examples of the possible technological advancements which can be made using the knowledge of physics
Answer:
1.it also hleps us to became doctors becuase without physics you can't be a doctor
2.physics needs to be steady whether you like it or not it helps you in life so everybody must study physics no matter is in Uganda USA and plenty more countries there must be physics to dare to be studied
Las carreras de velocidad pura en el atletismo son:
A. Un ladrón perseguido por la policia
B.100 y 200 mts planos
C. salir corriendo cuando la mama lo va a castigar
D.N.A
on
when you throw a ball
the
ground
and it
bounces back to your hand,
is it elastic collision ? Explain.
Answer:
The ground hits the ball with same force with which the balls hit the ground. That's why ball bounces back.
Gravity stops it from bouncing forever.
Hope this helps..
Help me frfr I don’t understand
The points are
(1,10)
(6,0)
[tex]\boxed{\sf slope(m)=\dfrac{y_2-y_1}{x_2-x_1}}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{0-10}{6-1}[/tex]
[tex]\\ \sf\longmapsto m=\dfrac{-10}{5}[/tex]
[tex]\\ \sf\longmapsto m=-2[/tex]
The magnetic coils of a tokamak fusion reactor are in the shape of a toroid having an inner radius of 0.700 m and an outer radius of 1.30 m. The toroid has 900 turns of largediameter wire, each of which carries a current of 14.0 kA. Find the magnitude of the magnetic field inside the toroid along (a) the inner radius and (b) the outer radius.
Answer:
(a) 11.3 T
(b) 6.09 T
Explanation:
Current, I = 14 kA = 14000 A
number of turns, N = 900
inner radius, r = 0.7 m
outer radius, R = 1.3 m
The magnetic field due to a circular coil is given by
[tex]B = \frac{\mu o}{4\pi}\times \frac{2 N\pi I}{R}[/tex]
(a) The magnetic field due to the inner radius is
[tex]B = 10^{-7}\times \frac{2\times 900\times 3.14\times 14000}{0.7}\\\\B = 11.3 T[/tex]
(b) The magnetic field due to the outer radius is
[tex]B = 10^{-7}\times \frac{2\times 900\times 3.14\times 14000}{1.3}\\\\B = 6.09 T[/tex]
Please help have due very soon?thank you
A particular electric car is supplied with 300 kJ of chemical energy by the battery. Of this, a total of 70.5 kJ of energy is wasted as heat.
Calculate the overall efficiency of the electric car.
Supplied energy=300kJ
Wasted energy=70.5JUsed energy:-
[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]
We know
[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]
[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]
[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]
The overall efficiency of the electric car = 76.5 %
To find the efficiency the given values are:
Energy supplied = 300 kJ
Energy wasted = 70.5 kJ
Define efficiency and calculate the value of efficiency.In the system the output energy is compared to the input energy is known as efficiency. That can be written as percentage ratio of output energy to the input energy.
Formula of efficiency is,
Efficiency = ( E out / E in ) × 100
Here, Energy supplied = 300 kJ
so, energy used = Energy supplied - Energy wasted
= 300 - 70.5
= 229.5 kJ
Thus, substituting E out = 300 kJ , E in = 229.5 kJ
Efficiency = ( 229.5 / 300 ) ×100
= 229.5 / 3
= 76.5
Hence, The overall efficiency of the electric car is 76.5 %
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What is the right hand rule for magnetic Force?
Answer:
The right hand rule states that, to find the direction of the magnetic force on a positive moving charge, the thumb of the right hand point in the direction of v, the fingers in the direction of B, and the force (F) is directed perpendicular to the right hand palm.
Explanation:
pls mark brainliest
Hope this helps u
