Answer:
The correct answer is d
Explanation:
In this exercise they ask us which statement is correct, for this we plan the solution of the problem, this is a Doppler effect problem, it is the frequency change due to the relative speed between the emitter and the receiver of sound.
The expression for the Doppler effect of a moving source is
f ’= (v / (v- + v_s) f
From this expression we see that if the speed the sound source is different from zero feels a change in the frequency.
The correct answer is d
Answer:
255 metres
Explanation:
The answer to thi question is actually quite simple. Since the car goes for 3.4 seconds, and it goes 75 metres every second, the answer is just 3.4 multiplied by 75 Metres.
Answer:
a. 3.039cm
b.magnetic field is 
Explanation:
Direction of the solenoid magnetic field is along the axis of the solenoid. and magnetic field due to the wire perpendicular to that due to the solenoid.. Magnetic field at r is given by:

Angle of net magnetic field from axial direction is given by:
,
Field due to solenoid:

Field due to wire:

Therefore, r:

Hence, the radial distance is 3.039cm
b.The magnetic field strength is given by:

Hence, the magnetic field is 
An electric current is an orderly, directed movement of electrically charged particles