Answer:
Explanation:
Givens
Vi = 10 m/s
Vf = 40 m/s
a = 3 m/s^2
Formula
a = (vf - vi) /t              Substitute the givens into this formuls
Solution
3 = (40 - 10) / t          Multiply both sides by t
3*t = t(40 - 10)/t        Combine. Cancel t's on the right
3*t = 30                     Divide by 3
3t/3 = 30 / 3
Answer: t = 10 seconds.
 
        
             
        
        
        
It hink that it is the 2nd one
 
        
                    
             
        
        
        
(a) Zero
The maximum efficiency (Carnot efficiency) of a heat engine is given by

where
 is the low-temperature reservoir
 is the low-temperature reservoir
 is the high-temperature reservoir
 is the high-temperature reservoir
For the heat engine in the problem, we have:


Therefore, the maximum efficiency is

(b) Zero
The efficiency of a heat engine can also be rewritten as

where
W is the work performed by the engine
 is the heat absorbed from the high-temperature reservoir
 is the heat absorbed from the high-temperature reservoir
In this problem, we know

Therefore, since the term  cannot be equal to infinity, the numerator of the fraction must be zero as well, which means
 cannot be equal to infinity, the numerator of the fraction must be zero as well, which means
W = 0
So the engine cannot perform any work.
 
        
             
        
        
        
Answer:
The most common of these is carbon 12, 13, 14. All of these isotopes have the same atomic number but different mass numbers. Carbon has the atomic number of 6 which means that all isotopes have the same proton number. However, the number of neutrons is different, thus giving different mass numbers.
 
        
             
        
        
        
I think comets because they are small and they are composed of ice or water. Hope it helps :)