Answer:
Explanation:
Let the intensity of the noise be represented by I
Given that
40dB = 10 log 10 ( I /I•) ........ 1
I• is the lowest or threshold intensity of sound made.
I represents the intensity of the sound/ noise
The intensity of noise of 1000flies will be
β = 10 log 10 (1000I/I•)
Open up the bracket
β = 10 log 10(1000)+ 10 log 10(I/I•)
10 log 10(10^3)+10 log 10(I/I•)
3×10(10 log 10) +10 log 10(I/I•)
Recall, 10 log 10 = 1
30×1 + 10 log 10(I/I•).........2
Put equation 1 into 2
β =30+40
= 70db
Refractive index is the ration of sin i to sin r where i is the incident angle and r is the refraction angle.
Therefore, refractive index = sin 79.5 / sin 39.6
= 1.542
The refractive index may be given by the ratio of refractive index of medium 2 to refractive index of medium 1.
Therefore, 1.542 = n/1.0003
n = 1.5425
≈ 1.54
Medium 2 is sodium chloride, refractive index of 1.54
Answer:
a). V = 3.13*10⁶ m/s
b). T = 1.19*10^-7s
c). K.E = 2.04*10⁵
d). V = 1.02*10⁵V
Explanation:
q = +2e
M = 4.0u
r = 5.94cm = 0.0594m
B = 1.10T
1u = 1.67 * 10^-27kg
M = 4.0 * 1.67*10^-27 = 6.68*10^-27kg
a). Centripetal force = magnetic force
Mv / r = qB
V = qBr / m
V = [(2 * 1.60*10^-19) * 1.10 * 0.0594] / 6.68*10^-27
V = 2.09088 * 10^-20 / 6.68 * 10^-27
V = 3.13*10⁶ m/s
b). Period of revolution.
T = 2Πr / v
T = (2*π*0.0594) / 3.13*10⁶
T = 1.19*10⁻⁷s
c). kinetic energy = ½mv²
K.E = ½ * 6.68*10^-27 * (3.13*10⁶)²
K.E = 3.27*10^-14J
1ev = 1.60*10^-19J
xeV = 3.27*10^-14J
X = 2.04*10⁵eV
K.E = 2.04*10⁵eV
d). K.E = qV
V = K / q
V = 2.04*10⁵ / (2eV).....2e-
V = 1.02*10⁵V
Answer:
Constant speed: yes
Constant velocity: no
Explanation:
Let's remind the definition of speed and velocity:
- Speed is a scalar quantity, which is equal to the ratio between the distance covered (regardless of the direction) and the time taken:
- Velocity is a vector quantity, so it has both a magnitude and a direction. The magnitude is equal to the rate between the displacement of the object and the time taken, while the direction is the same as the displacement.
In this problem, we notice that:
- The speed of the car remains constant, as it is 90 km/h
- However, its direction of motion changes while the car travels round the corner: this means that the direction of the velocity is also changing, therefore velocity is not constant.
