Answer:
Dark matter does not affect our view, humans can see through them.
Explanation:
They do not affect our view because we can see right through the (weakly interacting) dark matter, as they do not interact or interfere with electromagnetic force.
Dark matter are often invisible substances and are difficult to spot because they don't absorb or reflect light.
Answer:
c.
Explanation:
Initial velocity of cheetah,u=1 m/s
Time taken by cheetah =4.8 s
Final velocity of cheetah,v=28 m/s
We have to find the acceleration of this cheetah.
We know that
Acceleration,
Where v=Final velocity of object
u=Initial velocity of object
t=Time taken by object
Using the formula
Then, we get
Acceleration, a=
Acceleration=
Hence, the acceleration of cheetah=
Answer:
The velocity of the star is 0.532 c.
Explanation:
Given that,
Wavelength of observer = 525 nm
Wave length of source = 950 nm
We need to calculate the velocity
If the direction is from observer to star.
From Doppler effect

Put the value into the formula







Negative sign shows the star is moving toward the observer.
Hence, The velocity of the star is 0.532 c.
Answer:
As the tines of the tuning fork vibrate at their own natural frequency, they created sound waves that impinge upon the opening of the resonance tube. These impinging sound waves produced by the tuning fork force air inside of the resonance tube to vibrate at the same frequency.