Answer:
26.8 seconds
Explanation:
To solve this problem we have to use 2 kinematics equations: *I can't use subscripts for some reason on here so I am going to use these variables: 
v = final velocity 
z = initial velocity 
x = distance 
t = time 
a = acceleration 


First let's find the final velocity the plane will have at the end of the runway using the first equation:


Now we can plug this into the second equation to find t: 


Then using 3 significant figures we round to 26.8 seconds
 
        
             
        
        
        
Answer:
Mechanical energy is the energy that is possessed by an object due to its motion or due to its position. Mechanical energy can be either kinetic energy (energy of motion) or potential energy
 
        
             
        
        
        
I see the word "when..." kind of fading out at the end of the first line.
Whatever comes after it may be important.
If you're just supposed to copy the expression into the box,
then the problem is that you left the 'e' out of it.
I'm guessing that you're supposed to enter whatever the expression becomes
when either  N₀ or  ' t ' has some special value that's in the first line. 
Just taking a wild guess here . . . . .
If it's  "Enter the expression ..... , when t=0 ." ,
then the correct answer in the box is     N₀  . 
But that's just a wild guess.  As I pointed out, you cut off 
the picture in the middle of the word 'when', and I've got 
a hunch that there's something important after it.
        
             
        
        
        
Answer:
When an electron is hit by a photon of light, it absorbs the quanta of energy the photon was carrying and moves to a higher energy state. One way of thinking about this higher energy state is to imagine that the electron is now moving faster, (it has just been "hit" by a rapidly moving photon)
A photon is a quantum of EM radiation. Its energy is given by E = hf and is related to the frequency f and wavelength λ of the radiation by. E=hf=hcλ(energy of a photon) E = h f = h c λ (energy of a photon) , where E is the energy of a single photon and c is the speed of light.