Average speed is the ratio of total distance moved by Chi in total time interval
So here we will have
Total distance = 100 m + 400 m

Total time taken = 5 min + 15 min = 20 min

now by the formula of average speed we know that



so average speed will be 1.5 km/h
I believe the sun is the primary source of energy for Earth's weather system. The sun is the primary energy source for Earth's climate system which is the first set of essential principles of climate sciences. Additionally, it is the primary source that drives all weather events, including precipitation, hurricane and tornadoes. The sun drives the hydrologic cycle, and makes life on Earth possible.
Its B: reduce the amount of energy needed to do the work by putting the work onto something else
We make a graphic of this problem to define the angle.
The angle we can calculate through triangle relation, that is,

With this function we should only calculate the derivate in function of c

That is the rate of change of
.
b) At this point we need only make a substitution of 0 for c in the equation previously found.

Hence we have finally the rate of change when c=0.
Answer:
explained
Explanation:
Yes, the heating of filament is what causes the light production (photon emission), and this heating is caused because of current in the light bulb
(H= i^2*R*t i=current, H= heat, t= time and R= resistance).But using constant current source is not a good idea because in constant current source resistance is very low that can cause short circuit and ultimately fusing it. Whereas in constant voltage source current adjusts itself and prevents fusing because of high resistance in the circuit.