Answer:
(a) 62.5 m 
(b) 7.14 s
Explanation:
initial speed, u = 35 m/s 
g = 9.8 m/s^2 
(a) Let the rocket raises upto height h and at maximum height the speed is zero. 
Use third equation of motion 


h = 62.5 m 
Thus, the rocket goes upto a height of 62.5 m. 
(b) Let the rocket takes time t to reach to maximum height. 
By use of first equation of motion 
v = u + at 
0 = 35 - 9.8 t 
t = 3.57 s 
The total time spent by the rocket in air = 2 t = 2 x 3.57 = 7.14 second.
 
        
             
        
        
        
Answer:
of the velocity of a full size plane in the air
 
        
             
        
        
        
Answer:
The distance is  
 
Explanation:
From the question we are told that 
          The initial speed of the  electron is 
          The mass of electron is 
          Let  be the distance between the electron and the proton when the speed of the electron instantaneously equal to twice the initial value
 be the distance between the electron and the proton when the speed of the electron instantaneously equal to twice the initial value
          Let  be the initial kinetic energy of the electron \
 be the initial kinetic energy of the electron \
           Let  be the kinetic energy of the electron at the distance
 be the kinetic energy of the electron at the distance  from the proton
 from the proton 
   Considering that energy is conserved, 
   The energy at the initial position of the electron = The energy at the final position of the electron 
       i.e
              
 are the potential energy at the initial  position of the electron and at distance d of the electron to the proton
 are the potential energy at the initial  position of the electron and at distance d of the electron to the proton 
                 Here 
So the equation becomes 
                    
Here  are the charge on the electron and the proton and their are the same since a charge on an electron is equal to charge on a proton
 are the charge on the electron and the proton and their are the same since a charge on an electron is equal to charge on a proton 
   is electrostatic constant with value
 is electrostatic constant with value 
 i.e  
 
             is the velocity at distance d from the proton = 2
 is the velocity at distance d from the proton = 2
   So the equation becomes 
              
             ![\frac{1}{2} mv_i^2  = 4 [\frac{1}{2}mv_i^2 ]- \frac{k(q)^2}{d}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%20mv_i%5E2%20%20%3D%204%20%5B%5Cfrac%7B1%7D%7B2%7Dmv_i%5E2%20%5D-%20%5Cfrac%7Bk%28q%29%5E2%7D%7Bd%7D)
            ![3[\frac{1}{2}mv_i^2 ] = \frac{k(q)^2}{d}](https://tex.z-dn.net/?f=3%5B%5Cfrac%7B1%7D%7B2%7Dmv_i%5E2%20%5D%20%3D%20%5Cfrac%7Bk%28q%29%5E2%7D%7Bd%7D)
Making d the subject of the formula 
            
               
               
              
             
           
                   
    
 
        
             
        
        
        
Moving a spring back and forth creates a longitudinal wave