Astronomers believe some stars are moving away from earth by measuring the extent to which their light is “stretched” into the red part of the color spectrum, representing the lower frequencies on that spectrum.
In short, stars moving away from earth are “red-shift”, while if they were moving towards the earth they would take on a “blue-shift”.
Answer:
C) 6 m/s
Explanation:
Given that
m₁=5000 kg
The initial velocity of 5000 kg car =u₁
m₂=10,000 kg
The initial velocity of 10000 kg car =u₂ = 0 m/s
After collision the final speed of the both car,v = 2 m/s
There is no any external force on the system that is why linear momentum will be conserved.
Linear momentum P = m v
m₁u₁ + m₂u₂ = (m₂ + m₁) v
5000 x u₁ + 10000 x 0 = (5000 + 10000) x 2
5000 x u₁ = 15000 x 2
5 x u₁ = 15 x 2
u₁ = 6 m/s
Therefore the answer is C.
C) 6 m/s
(a) 10 GHz is the frequency of microwave radiation.
(b) 0.167 ms is required by the microwave to travel between two mountains.
Answer:
Explanation:
(a). 1 MHz is the frequency of microwave radiation.
(b) 0.167 ms is required by the microwave to travel between two mountains.
Answer:
Explanation:
a. Frequency is the measure of number of times a same thing will be repeated in a given time interval for a given time. And wavelength is the measure of distance between two successive crests or troughs. So wavelength and frequency are inversely proportional to each other. And velocity of light is the proportionality constant.
So frequency of microwave radiation = Speed of light/Wavelength of radiation
Frequency = ![\frac{3*10^{8} }{3*10^{-2} }](https://tex.z-dn.net/?f=%5Cfrac%7B3%2A10%5E%7B8%7D%20%7D%7B3%2A10%5E%7B-2%7D%20%7D)
Frequency = ![10^{8+2} = 10^{10}=10 GHz](https://tex.z-dn.net/?f=10%5E%7B8%2B2%7D%20%3D%2010%5E%7B10%7D%3D10%20GHz)
So 10 GHz is the frequency of microwave radiation.
b). As microwave is a part of light waves, so it will be experiencing the speed of light.
As the speed is 3*
m/s and the distance between the two mountains is given as 50 km, then time can be calculated as
Time = Distance/Velocity
Time = ![\frac{50*10^{3} m}{3*10^{8} }=16.67*10^{3-8}=16.67*10^{-5}](https://tex.z-dn.net/?f=%5Cfrac%7B50%2A10%5E%7B3%7D%20m%7D%7B3%2A10%5E%7B8%7D%20%7D%3D16.67%2A10%5E%7B3-8%7D%3D16.67%2A10%5E%7B-5%7D)
So time = 0.167 ms.
Thus, 0.167 ms is required by the microwave to travel between two mountains.
Answer:
The recoil velocity is 0.354 m/s.
Explanation:
Given that,
Mass of hunter = 70 kg
Mass of bullet = 42 g = 0.042 kg
Speed of bullet = 590 m/s
We need to calculate the recoil speed of hunter
Using conservation of momentum
![m_{1}u_{1}+m_{2}u_{2}=m_{1}v_{1}+m_{2}v_{2}](https://tex.z-dn.net/?f=m_%7B1%7Du_%7B1%7D%2Bm_%7B2%7Du_%7B2%7D%3Dm_%7B1%7Dv_%7B1%7D%2Bm_%7B2%7Dv_%7B2%7D)
Where,
= mass of hunter
= mass of bullet
u = initial velocity
v = recoil velocity
Put the value in the equation
![0+0=70\times v_{1}+0.042\times590](https://tex.z-dn.net/?f=0%2B0%3D70%5Ctimes%20v_%7B1%7D%2B0.042%5Ctimes590)
![v_{1}=-\dfrac{0.042\times590}{70}](https://tex.z-dn.net/?f=v_%7B1%7D%3D-%5Cdfrac%7B0.042%5Ctimes590%7D%7B70%7D)
![v=-0.354\ m/s](https://tex.z-dn.net/?f=v%3D-0.354%5C%20m%2Fs)
Hence, The recoil velocity is 0.354 m/s.
Answer:
the meaning of conduction is the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material.
Explanation: