Answer:B
Explanation:
Given
speed of car 
mass of clump 
Radius of car tire 
Since the tire is rotating about axle so a centripetal force is acting constantly on each particle towards the center of tire.
Centripetal force is given by

where 



(inward)
A star may form a black hole
once is true. After the marked supernova explosion, the star shrinks because it
sheds away the gaseous layers of the star. And especially if the star is large,
it will form into a black hole.
1) The velocity of the particle is given by the derivative of the position. So, if we derive s(t), we get the velocity of the particle as a function of the time:

2) The acceleration of the particle is given by the derivative of the velocity. So, if we derive v(t), we get the acceleration of the particle as a function of the time:

Explanation:
Two waves with the same wavelength are in phase if there phase difference is zero or an integral multiple of wavelength. Thus the integer part of any difference expressed in wavelength can be discarded.
The phase difference of 5.4 wavelength is equivalent to is one of 0.4 wavelength thus the interference is an intermediate interference close to fully destructive.
I think there is 19 protons