Answer:
Explanation:
Given
car A had a head start of 
and it starts at x=0 and t=0
Car B has to travel a distance of 
where
is the distance travel by car A in time t
distance travel by car A is

For car B with speed 



Answer:
3.1 m/s
Explanation:
The total distance she has to run is the addition of the three lengths:
47 + 63 + 76 = 186 meters.
She needs to cover it one minute (60 seconds). Therefore her speed must be:
186 m / 60 s = 3.1 m/s
Answer:
That the universe (the balloon for this case) is expanding and that is the reason why the galaxies (the dots) appear to move away one from another.
Explanation:
By means of looking at the spectra of galaxies, it can confirm that they are moving away in an accelerated motion.
Spectral lines will be shifted to the blue part of the spectrum if the source of the observed light is moving toward the observer, or to the red part of the spectrum when it is moving away from the observer (that is known as the Doppler effect). The source in this particular case is represented for each of the galaxies.
Hence, the redshift represents this shift of the spectral lines to red part in the spectrum of a galaxy or any object which is moving away. That is a direct confirmation of how the universe is in an expanding accelerated motion.
The redshift can be define in analitic way by trought the doppler velocity:
(1)
Where
is the wavelength shift,
is the wavelength at rest, v is the velocity of the source and c is the speed of light.
(2)
Where z is the redshift.
The ballon example, once that it is inflating, represents how is the universe which it is expanding and that is the reason why the galaxies (the dots) appear to move away one from another.
Acceleration = (final velocity-initial velocity)/time
5 = (v-0)/20
v = 100m/s