At the present time, the only way we know of that light can get shifted
toward the blue end of the spectrum is the Doppler effect ... wavelengths
appear shorter than they should be when the source is moving toward us.
IF that's true in the case of the Andromeda galaxy, it means the galaxy is
moving toward us.
We use the same reasoning to conclude that all the galaxies whose light is red-shifted are moving away from us. That includes the vast majority of all galaxies that we can see, and it strongly supports the theory of the big bang
and the expanding universe.
If somebody ever comes along and discovers a DIFFERENT way that light
can get shifted to new, longer or shorter wavelengths, then pretty much all
of modern Cosmology will be out the window. There's a lot riding on the
Doppler effect !
Answer:
Part a)

Part b)

Part c)

Explanation:
Part a)
As we know that ball will reach at maximum height at
t = 3 s
now we will have

now we have


Now maximum height above ground is given as



Part b)
Height of the fence is given as



Part c)
As we know that its horizontal distance moved by the ball in 5.5 s is given as



now total time of flight is given as

so range is given as



so the distance from the fence is given as


Answer:60 gm
Explanation:
Given
initial velocity of ball 
Force exerted by racquet 
time period of force 
final velocity of ball 
Racquet imparts an impulse to the ball which is given by



Answer:
The minimum speed = 
Explanation:
The minimum speed that the rocket must have for it to escape into space is called its escape velocity. If the speed is not attained, the gravitational pull of the planet would pull down the rocket back to its surface. Thus the launch would not be successful.
The minimum speed can be determined by;
Escape velocity = 
where: G is the universal gravitational constant, M is the mass of the planet X, and R is its radius.
If the appropriate values of the variables are substituted into the expression, the value of the minimum speed required can be determined.
Answer:
To find the mass using density and volume we just multiply them against each other which causes ml to cancel and just leaves us with grams which represents how much the item weights.



Therefore, our final answer is that our pencil weight 3.5 grams
<u><em>Hope this helps! Let me know if you have any questions</em></u>