Answer:
A.) Time = 0.625 hrs = 37.5 minutes
B.) Speed required = 133.33km/hr
Explanation:
Given the following :
Total race distance = 100km
Total time required = 1 hour = 60 minutes
Average speed after traveling 50km = 80km/hr
80km/hr : This means it will take one hour to cover a distance of 80km
Therefore, time taken to cove first 50km at that average speed equals :
1 hour = 80 km
t hours = 50km
80t = 50
t = 50/80
t = 5/8 hours
t = 0.625hours
t = 0.625 * 60 = 37.5minutes
B)
Average speed required to complete the race in 1 hour = 100km/hr
Time used to complete first 50km = 0.625 hour
Time remaining: (1 - 0.625) hour = 0.375
Speed required = Distance left / time left
Speed required = 50 / 0.375
Speed required = 133.33km/hr
B. A sandbar is formed by water. A sand dune is formed by wind.
Nuclear fission formula by the looks of it. Possibly how Professor Lisa Meitner realised that she had split the atomic nucleus. The Xenon and the Strontium (Xe and Sr) would presumably show up in a radio chemical assaying test at her university.
A few years later, Professor J Robert Oppenheimer watched a nuclear test somewhere near Los Alamos, US and lamented "I am become death, the destroyer of worlds". Shortly thereafter, Hiroshima and Nagasaki were razed to the ground and annihilated by nuclear bombs. Professor Meitner, probably inadvertently, had got the keys to the doors to "nuclear hell", and JRO ended up turning them. Something like that maybe, and a very harrowing and tumultuous period in human history.
Note in the fission equation, that out come two neutrons. They go off and produce a similar fission in another U235 nucleus into a chain reaction which, i not moderated by, say, Boron, can end up as a "mushroom cloud".
Heat always flows from higher temperature to lower temperature. So option A. heat will flow from the air into the coolant is the correct answer.
Answer: v= 160ft/s
a=32ft/s^2 constant
Explanation:
s(t)=400-16t^2 derivative of position is velocity v(t) and derivative of velocity is acceleration a(t) so let s(t)=0 to find the time of flight to reach the ground and take the two derivatives and use the time found and solve. Also acceleration is a constant as it’s gravity.
0=400-16t^2
400=16t^2
25=t^2
t=5s
ds/dt=v(t)=0-32t
dv/dt=a(t)=-32 constant(gravity)
v(t)=-32(5s)= -160ft/s negative sign is only showing direction