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:
T = 17649.03 N = 17.65 KN
Explanation:
The tension in the cable must be equal to the apparent weight of the passenger. For upward acceleration:

where,
T = Tension in cable = ?
= Apparent weight
m = mass = 1603 kg
g = acceleration due to gravity = 9.81 m/s²
a = acceleration of elevator = 1.2 m/s²
Therefore,

<u>T = 17649.03 N = 17.65 KN</u>
Answer:
a) 
b) 
c) 
d)
or 18.3 cm
Explanation:
For this case we have the following system with the forces on the figure attached.
We know that the spring compresses a total distance of x=0.10 m
Part a
The gravitational force is defined as mg so on this case the work donde by the gravity is:

Part b
For this case first we can convert the spring constant to N/m like this:

And the work donde by the spring on this case is given by:

Part c
We can assume that the initial velocity for the block is Vi and is at rest from the end of the movement. If we use balance of energy we got:

And if we solve for the initial velocity we got:

Part d
Let d1 represent the new maximum distance, in order to find it we know that :

And replacing we got:

And we can put the terms like this:

If we multiply all the equation by 2 we got:

Now we can replace the values and we got:


And solving the quadratic equation we got that the solution for
or 18.3 cm because the negative solution not make sense.
Answer:
false statement : b ) For the motion of a cart on an incline plane having a coefficient of kinetic friction of 0.5, the magnitude of the change in kinetic energy equals the magnitude of the change in gravitational potential energy
Explanation:
mechanical energy = potential energy + kinetic energy = constant
differentiating both side
Δ potential energy + Δ kinetic energy = 0
Δ potential energy = - Δ kinetic energy
first statement is true.
Friction is a non conservative force so inter-conversion of potential and kinetic energy is not possible in that case. In case of second option, the correct relation is as follows
change in gravitational potential energy = change in kinetic energy + work done against friction .
So given 2 nd option is incorrect.
In case of no change in gravitational energy , work done is equal to
change in kinetic energy.