Answer:

Explanation:
As we know that
velocity of bike = 7.5 m/s
velocity of car is 10 m/s
deceleration of car is 0.75 m/s^2
part a)
velocity of bike with respect to car is given as

acceleration of bike with respect to car is given as

now the distance of the bike with respect to car is given as



Part b)
Im guessing it's (a) since the numbers go in chronological order and you read the periodic table left to right
Answer:
cargo planes hold cargo so there hevier
Explanation:
Answer:
A. The wavelengths of the new sound waves are longer
Explanation:
This is the Doppler effect which can be best illustraded for the case of a siren of an ambulance approaching us having a greater frequency and getting lower in frequency and deeper as the ambulance passes us.
Since the wavelength is inversely proportional to the frequency it follows the wavelengths are longer when the frequency decreases lowering its pitch and getting deeper.
Light travelling in a vacuum is the fastest thing in the universe. The speed would be 2.99x10^8 m/s. The answer to this question is 'vacuum', where light can travel the fastest. I hope this helps you. You're welcome!