Answer:
The frequency is 302.05 Hz.
Explanation:
Given that,
Speed = 18.0 m/s
Suppose a train is traveling at 30.0 m/s relative to the ground in still air. The frequency of the note emitted by the train whistle is 262 Hz .
We need to calculate the frequency
Using formula of frequency

Where, f = frequency
v = speed of sound
= speed of passenger
= speed of source
Put the value into the formula


Hence, The frequency is 302.05 Hz.
Answer:

Explanation:
Mass of the helium gas filled inside the volume of balloon is given as




now total mass of balloon + helium inside balloon is given as


now we know that total weight of balloon + cargo = buoyancy force on the balloon
so we will have




It is C. A description goes into the details about something, and an explanation is a statement that clarifies something, generally a question.
Answer:
Q=+100kj,w=-15kj,Q=100kj,w=-62kj
Explanation:
when energy is exerted into a system work done is equal to zero .hence the system does work to the surrounding.
Answer:
65.2 %
Explanation:
Let Q1 = Heat absorbed by the system
Q2 = Heat released by the system
e= (1 - (Q2/Q1)) x 100
e= (1 - (750/2150)) x 100
e= (1 - 0.348) x 100
e= 0.652 x 100
e= 65.2 %