Answer:
They can't hear an echo in small room because in it the sound can't be reflected back. For an echo of a sound to be heard,the minimum distance between the source of sound and the walls of the room should be 17.2 m.
hopw it helps
Density reduces
Explanation:
The density of a fluid will reduce as a substance gains more thermal energy. Heat is a form of thermal energy usually noticed as temperature differences in a matter.
- When thermal energy is gained by a body, the temperature of the body rises.
- The particles of the medium gains more kinetic energy.
- This causes the substance to expand and it has more volume.
- When a substance expands, it occupies more space.
- The more the volume a body occupies, the lesser the density.
- Expansion does not change the mass of the fluid but the volume changes.
- This is why density decreases.
Learn more:
Density brainly.com/question/8441651
#learnwithBrainly
Answer:
Explanation:
a) Power consumption is 4100 J/min / 60 s/min = 68.3 W(atts)
work done raised the potential energy
b) 75(9.8)(1000) / (3(3600)) = 68.055555... 68.1 W
c) efficiency is 68.1 / 68.3 = 0.99593... or nearly 100%
Not a very likely scenario.
Answer:
162500000.
Explanation:
Given that
Diameter of the wire , d= 1.8 mm
The length of the wire ,L = 15 cm
Current ,I = 260 m A
The charge on the electron ,e= 1.6 x 10⁻¹⁹ C
We know that Current I is given as
I=Current
q=Charge
t=time
q= I t
q= 260 m t
The total number of electron = n
q= n e
n=162500000 t
The number of electron passe per second will be 162500000.
Answer:
a) 17.49 seconds
b) 13.12 seconds
c) 2.99 m/s²
Explanation:
a) Acceleration = a = 1.35 m/s²
Final velocity = v = 85 km/h =
Initial velocity = u = 0
Equation of motion
Time taken to accelerate to top speed is 17.49 seconds.
b) Acceleration = a = -1.8 m/s²
Initial velocity = u = 23.61\ m/s
Final velocity = v = 0
Time taken to stop the train from top speed is 13.12 seconds
c) Initial velocity = u = 23.61 m/s
Time taken = t = 7.9 s
Final velocity = v = 0
Emergency acceleration is 2.99 m/s² (magnitude)