Answer:
a
e(k) = \frac{2a}{c} * sin (\frac{k*a}{2} )
b
G_{v} = \frac{d e(k ) }{dk } = \frac{a^2}{c} * cos (\frac{k* a}{2} )
Explanation:
From the question we are told that
The velocity of transverse waves in a crystal of atomic separation is

Generally the dispersion relation is mathematically represented as

=> 
=> 
=> 
Generally the group velocity is mathematically represented as

Answer:
6.46393559312 m/s²
Explanation:
Time taken to cover 56 m

Distance covered in 0.42 seconds

From equation of linear motion


The minimum acceleration is 6.46393559312 m/s²
Scientific form = 6.5 x 109.
Answer:
D. Electromagnetic Induction.
Explanation:
The static frictional force is greater than the kinetic frictional force, so the static frictional force is greater than 1200 N.