Answer:
Wavelength, 
Explanation:
Given that,
Number of cycles in a spiral spring is 2.91 in every 3.67 s
The velocity of the pulse in the spring is 0.925 cm/s, v = 0.00925 m/s
To find,
Wavelength
Solution,
Number of cycles per unit time is called frequency of a wave. The frequency of the longitudinal pulse is,

The wavelength of a wave is given by :



So, the wavelength of the longitudinal pulse is 0.011 meters. Hence, this is the required solution.
First we will find the speed of the ball just before it will hit the floor
so in order to find the speed of the cart we will first use energy conservation



So by solving above equation we will have

now in order to find the momentum we can use



Answer:
Energy density will be 14.73 
Explanation:
We have given capacitance 
Potential difference between the plates = 365 V
Plate separation d = 0.200 mm 
We know that there is relation between electric field and potential
, here E is electric field, V is potential and d is separation between the plates
So 
Energy density is given by