Answer: small cars can stop and go fast big trucks can not
Explanation:
Iron, and lack of red blood cells can cause anemia so you'd need those to prevent it.
Answer: The answer: The car is moving away from you.
Both A and C are true as Car can be moving in line away from you or has component of velocity in opposite direction.
Explanation:The decrease in the frequency of the sound is the result of Doppler's effect. A/c to Doppler's effect the frequency of received sound of source is changed if it is moving relative to the receiver, i.e. the distance between them is changing due to motion.
The general formula of Doppler's Effect is attached as the picture.
In this formula v_D is the velocity of Detector i.e the receiver relative to wind. While v_s is the velocity of source relative to wind and v is the velocity of sound.
The Doppler's effect is not effected by the velocity of wind as the wind itself could not change the distance between the two objects i.e. you and the car. Wind velocity can change the speed of sound and its wavelength but the change does not effect the frequency.
Hence if we assume the car to be moving with velocity v_c and you are stationary

hence the frequency is reduced.
Answer:
The the maximum emf is 
Explanation:
Given that,
Magnetic field 
Frequency = 60 Hz
Diameter = 7.8 μm
We need to calculate the maximum emf
Using formula of emf

Where, N = number of turns
B= magnetic field
A = area
Put the value in to the formula


Hence, The the maximum emf is 
Answer:
a) E = 8628.23 N/C
b) E = 7489.785 N/C
Explanation:
a) Given
R = 5.00 cm = 0.05 m
Q = 3.00 nC = 3*10⁻⁹ C
ε₀ = 8.854*10⁻¹² C²/(N*m²)
r = 4.00 cm = 0.04 m
We can apply the equation
E = Qenc/(ε₀*A) (i)
where
Qenc = (Vr/V)*Q
If Vr = (4/3)*π*r³ and V = (4/3)*π*R³
Vr/V = ((4/3)*π*r³)/((4/3)*π*R³) = r³/R³
then
Qenc = (r³/R³)*Q = ((0.04 m)³/(0.05 m)³)*3*10⁻⁹ C = 1.536*10⁻⁹ C
We get A as follows
A = 4*π*r² = 4*π*(0.04 m)² = 0.02 m²
Using the equation (i)
E = (1.536*10⁻⁹ C)/(8.854*10⁻¹² C²/(N*m²)*0.02 m²)
E = 8628.23 N/C
b) We apply the equation
E = Q/(ε₀*A) (ii)
where
r = 0.06 m
A = 4*π*r² = 4*π*(0.06 m)² = 0.045 m²
Using the equation (ii)
E = (3*10⁻⁹ C)/(8.854*10⁻¹² C²/(N*m²)*0.045 m²)
E = 7489.785 N/C