Because cold air tends to more dense, and it's therefore heavier, and it sinks.
Hot air though is hot with no density so it's light and rises.
        
                    
             
        
        
        
<span>a = ΔV/Δt = (5000-10000)/60 = -500/6 = -83.(3) m/sec^2</span>
        
                    
             
        
        
        
Answer:
  E = 2,964 10⁻¹⁹ J
Explanation:
The energy of the photons is given by the Planck relation
           E = h f
the speed of light is related to wavelength and frequency
           c = λ f
we substitute
           E = h c /λ
let's reduce the magnitude to the SI system
           λ = 671 nm = 671 10⁻⁹ m
let's calculate
           E = 6.63 10⁻³⁴ 3 10⁸ /671 10⁻⁹
           E = 2,964 10⁻¹⁹ J
 
        
             
        
        
        
Choices  1,  2,  and 4 . . . . . Yes
Choices  3  and 5 . . . . . No
        
             
        
        
        
Answer:
v = 10 m/s
Explanation:
Given that,
Distance covered by a sprinter, d = 100 m
Time taken by him to reach the finish line, t = 10 s
We need to find his average velocity. We know that velocity is equal to the distance covered divided by time taken. So,
v = d/t

Hence, his average velocity is 10 m/s.