Answer:
<u>because of the doppler effect</u>
Explanation:
<em>Remember</em>, the doppler effect refers to the changes in sound (frequency of sound) observed by a person who is in a position relative to the wave source.
In this example, we notice as the train comes closer to the boy, the sound becomes louder also increasing the pitch slightly, the doppler effect sets in when the train passes the boy because the boy notices a decrease in the pitch of the moving train.
We learn from the change in the observed sound of the train that the frequency of the sound is determined by the distance of the observer from the wave source.
In other words, the closer the source of the sound to the observer; the faster it travels to the observer, however, the farther it is; the lesser it is; the greater the sound heard.
Answer:
0.2687 approximately 0.27
Explanation:
Diameter = 0.320
Speed = 40.0 rev/min
We are required to find coefficient of static friction between friction and button
The radius can be calculated as
0.320/2
= 0.160m
Then we have the rotational speed w = 40rev/min x 2pi/60
= 4.19 rad/s
umg = mrw²
u = mrw²/mg
u = rw²/g -------(1)
g = 9.8
When we put values into equation 1
0.150m x 4.19² / 9.8
= 0.150m x 17.5561 /9.8
= 0.2689
This is approximately 0.27
Answer:
m≈501.57 g
Explanation:
The density formula is:
d=m/v
Let’s rearrange the formula for m. m is being divided by v. The inverse of division is multiplication, so multiply both aides by v.
d*v= m/v*v
d*v=m
The mass can be found by multiply the density and the volume.
m=d*v
The density is 1.06 grams per milliliter and the volume is 473.176 milliliters.
d= 1.06 g/mL
v= 473.176 mL
Substitute the values into the formula.
m= 1.06 g/mL * 473.176 mL
Multiply. When multiplying, the mL will cancel out.
m= 501.56656 g
Let’s round to the nearest hundredth. The 6 in the thousandth place tells us to round the 6 to a 7 in the hundredth place.
m ≈501.57 g
The mass is about 501.57 grams.
Answer:
1. 0.574 kJ/kg
2. 315.7 MW
Explanation:
1. The mechanical energy per unit mass of the river is given by:
Where:
Ek is the kinetic energy
Ep is the potential energy
v is the speed of the river = 3 m/s
g is the gravity = 9.81 m/s²
h is the height = 58 m
Hence, the total mechanical energy of the river is 0.574 kJ/kg.
2. The power generation potential on the river is:
Therefore, the power generation potential of the entire river is 315.7 MW.
I hope it helps you!
