Answer:
The correct answer is "4.26 m".
Explanation:
Given:
Wavelength,

or,

Distance,

or,

Distance between the 1st and 2nd dark fringes,
As we know,
⇒ 
or,
⇒ 
By substituting the values, we get




To develop this problem it is necessary to apply the concepts related to the Dopler effect.
The equation is defined by

Where
= Approaching velocities
= Receding velocities
c = Speed of sound
v = Emitter speed
And

Therefore using the values given we can find the velocity through,


Assuming the ratio above, we can use any f_h and f_i with the ratio 2.4 to 1


Therefore the cars goes to 145.3m/s
I think it’s D................
Answer:

Explanation:
The correct equation follows the law of conservation of energy where kinetic energy is all transformed to potential energy, since we know that kinetic energy is expressed as
while potential energy is mgh where m is the mass of the object, v is the velocity or speed of the object, g is acceleration due to gravity and h is the vertical height. Therefore, relating the two equations we should have 
Experiments and investigations must be B. Repeatable.