Answer:
24.71 mm
Explanation:
Distance is proportional to focal length, so
d∝f
which means
Magnification of first lens
and
Similarly, magnification of second lens
and
From the above equations we get
and
which means,
and
So, we get
∴ Focal length should this camera's lens is 24.71 mm
Answer:
The magnitude of the acceleration of the car is 35.53 m/s²
Explanation:
Given;
acceleration of the truck, = 12.7 m/s²
mass of the truck, = 2490 kg
mass of the car, = 890 kg
let the acceleration of the car at the moment they collided =
Apply Newton's third law of motion;
Magnitude of force exerted by the truck = Magnitude of force exerted by the car.
The force exerted by the car occurs in the opposite direction.
Therefore, the magnitude of the acceleration of the car is 35.53 m/s²
Answer:
The correct answer is option 'd': The frequency decreases and the intensity of the sound decreases.
Explanation:
1) <u>Effect on Frequency </u>
According to Doppler's effect of sound we have
for a source of sound moving away from the observer the relation between the observed and the original frequency is given by
where
c = speed of sound in air
is the velocity of observer of sound
is the velocity of source of sound
is the original frequency of sound
As we see the ratio is less than 1 thus the frequency of sound that the observer receives is less than that of source.
2) <u>Effect on Intensity:</u>
At a distance 'r' from source emitting a wave of Power 'P' is given by
As we see on increasing 'r' intensity of sound decreases.