Answer:
fo = 378.52Hz
Explanation:
Using Doppler effect formula:

where
f' = 392 Hz
C = 340m/s
Vb = 20m/s
Va = 31m/s
Replacing these values and solving for fo:
fo = 378.52Hz
Answer:
5 ohms
Explanation:
Given:
EMF of the ideal battery (E) = 60 V
Voltage across the terminals of the battery (V) = 40 V
Current across the terminals (I) = 4 A
Let the internal resistance be 'r'.
Now, we know that, the voltage drop in the battery is given as:
Therefore, the voltage across the terminals of the battery is given as:

Now, rewriting in terms of 'r', we get:

Plug in the given values and solve for 'r'. This gives,

Therefore, the internal resistance of the battery is 5 ohms.
Answer:
a
Explanation:
The angular speed of a rotating platform changes from.at a constant rate as the platform moves through an angle
Answer:
Explanation:
initial velocity = 24m/s
final velocity = 0 ( since she is coming to a rest )
time = 12 s
∴ acceleration = final velocity - initial velocity / time
= 0 -24 / 12
= -24/12
= -2 m/s
hope this helps
plz mark it as brainliest