v = speed of the source of sound or the train towards the listener or switchman = 40 m/s
V = actual speed of sound = 340 m/s
f = actual frequency of sound as emitted from source or the train = 1000 Hz
f' = frequency as observed by the listener or by switchman = ?
Using Doppler's law , frequency observed by a listener from a source moving towards it is given as
f' = V f /(V - v)
inserting the values
f' = 340 x 1000 /(340 - 40)
f' = 340 x 1000/300
Answer:
Option B
Explanation:
Given information
Radius of container, r=12cm=12/100=0.12m
Angular velocity= 2 rev/s, converted to rad/s we multiply by 2π
Angular velocity, 
We know that speed, 
Centripetal acceleration, 
and substituting we obtain that
Substituting \omega for 12.56637061 and r for 0.12
Rounded off,
1h----------------> 70x3=210 bacteria
2h-----------------> 210*3=630 bactaeria
let be y the number of bacteria at the t=0h
it is y=70 3^0
for t= 1h
y=70*3^1=210
for t=2h
y=70*3^2=630
so we can write y=70*3^x, where x is the number of hour
I believe if it were heavier with more mass, then the sun would pull it in and there would be no mercury. It might also be hotter.
Answer:
E_total = 1.30 10¹⁰ C / m²
Explanation:
The intensity of the electric field is
E = k q / r²
on a positive charge proof
The total electric field at the midpoint is
as q₁= 6 10⁻⁶ C the field is outgoing to the right
for charge q₂ = -3 10⁻⁶ C, the field is directed to the right, therefore
E_total = E₁ + E₂
E_total = k q₁ / r₁² + k q₂ / r₂²
r₁ = r₂ = r = 4 10⁻² m
E_total = k/r² (q₁ + q₂)
we calculate
E_total = 9 10⁹ / (4 10⁻²)² (6.0 10⁻⁶ +3.0 10⁻⁶)
E_total = 1.30 10¹⁰ C / m²
