Let say the two train cars are of masses 
and 
now if the speed of two cars are 
and 
then we can say that the momentum of two cars before they collide is given by
here two cars are moving in opposite direction so we can say that the net momentum is subtraction of two cars momentum.
Now since in these two car motion there is no external force on them while they collide
So the momentum of two cars are always conserved.
hence we can say that the final momentum of two cars will be same after collision as it is before collision
<span>We know , E = kQ/r^2 where q = charge and r is separation between point and point charge.
Now, At P, E= kQ/r^2
Since, Q can't be changed, we can do that by varying r
2E = 2kq/r^2
2E = kq/ (r/ sqrt2)^2
Hence, if we bring Q closer such that distance between P and Q becomes r/ sqrt 2, E will get doubled.</span>
Answer:
The value is 
Explanation:
From the question we are told that
The length of the crack is 
The frequency is 
The distance outside the cave that is being consider is 
The speed of sound is 
Generally the wavelength of the wave is mathematically represented as
=> 
=> 
Generally for a single slit the path difference between the interference patterns of the sound wave and the center is mathematically represented as
=> 
=> 
Generally the width of the sound beam is mathematically represented as
=> 
=>
It’s C because just trust
