The formula is:
v = v o + a t
6 = 10 + 3 * a
3 a = 10 - 6
a = 4 : 3
a = - 1.33 m/s² ( because the car slows down )
Answer: The average acceleration of the car is - 1.33 m/s²
Answer:
a. wavelength of the sound, 
b. observed frequecy, 
Given:
speed of sound source,
= 80 m/s
speed of sound in air or vacuum,
= 343 m/s
speed of sound observed,
= 0 m/s
Solution:
From the relation:
v =
(1)
where
v = velocity of sound
= observed frequency of sound
= wavelength
(a) The wavelength of the sound between source and the listener is given by:
(2)
(b) The observed frequency is given by:


(3)
Using eqn (2) and (3):


Answer:
The correct answer is B.
The astronaut will know due to the light from the explosion.
Explanation:
Sound and vibrations require a medium such as air to travel through. Space, there is no air. Only a vacuum. So sound and vibrations are unable to travel. Light requires no medium to travel. It can go through a vacuum.
Therefore the Astronaut will see a bright flash of light as it travels from the explosion to outer space. It is also important to note that light can travel very far because nothing else interacts with its wave particles and as such, it cannot be impeded.
Cheers!