Answer:
B. the stars to come back to the same positions in the sky.
Explanation:
In fact, the solar day is equivalent to more than a rotation, because when the point has turned completely, it is not, as it should, in the same position with respect to the Sun.
The reason for this is that while performing the rotation, the Earth simultaneously moved following its orbit around the Sun.
When the reference point completed its rotation, the Earth already moved almost 2,500,000 km., So that to see the Sun again it will be necessary to turn a little more.
Solar day is more than a rotation. The sidereal or sidereal day, commonly used by astronomers, is also based on the rotation of the Earth; but in this case a distant star is taken as a reference (sidereal comes from the Latin sidus which means "star").
Answer:
0.0675 seconds
Explanation:
From the question,
We apply newton's second law of motion
F = m(v-u)/t.................... Equation 1
Where F = force exert by the brake, v = final speed, u = initial speed m = mass of the bicycle, t = time.
make t the subject of the equation
t = m(v-u)/F................... Equation 2
Given: m = 180 kg, u = 6.0 m/s, v = 0 m/s (comes to stop), F = -1600 N ( agianst the dirction of motion)
Substitute these value into equation 2
t = 180(0-6.0)/-1600
t = -1080/-1600
t = 0.0675 seconds.
To solve this problem we will apply the concepts related to electric potential and electric potential energy. By definition we know that the electric potential is determined under the function:
= Coulomb's constant
q = Charge
r = Radius
At the same time
The values of variables are the same, then if we replace in a single equation we have this expression,
If we replace the values, we have finally that the charge is,
Therefore the potential energy of the system is 
There are three types of heat conduction through substances. These are named as conduction,convection and radiation .here we have been given convection.
Convection is the type of mode of conduction of heat in which heat will flow though a liquid and gases due to the direct physical movement of particles.In this process the hotter particles will go upward as they become lighter and cooler,heavier particles come downward which after being heated up go upward .Hence a convectional current is formed for which whole of the liquid or gas gets heated.
There are different life examples of convection.
One may take an simple example of water in a container.The water molecules which are present bottom part of the container will be heated up first and go upward.The upper particles will come downward and they will constitute a convectional current.
Another life example is the flow of wind from one region to another region.the air at hotter region will become lighter and goes upward and the wind starts flowing from cold region region in order to occupy the vacant space.
Another example is the hot air balloon rising up..It is also another example of convection of heat
