Question:
Consider a sample of helium gas in a container fitted with a piston as pictured below. The piston is frictionless, but has a mass of 10.0 kg. How many of the following processes will cause the piston to move away from the base and decrease the pressure of the gas? Assume ideal behavior.
I. Heating the helium. II.
II. toRemoving some of the helium from the container.
III. Turning the container on its side.
IV. Decreasing the pressure outside the container.
a) 0
b) 1
c) 2
d) 3
e) 4
Answer:
Only one process will cause the piston to move which is
i) Heating the helium
Explanation:
When helium is heated it becomes less dense or lighter. Heating the helium will cause an increase in volume which will make the piston to move away from the base. When the volume finishes increasing, the piston will stop moving which in turn will make the forces on both sides of the piston balanced, so the pressure inside will balance the weight of the piston and that of the atmosphere. From that we can see that there has been a pressure change as a result of heating.
Explanation:
The frequency is given to be f = 8 Hz.
Period is the inverse of frequency.
T = 1/f = 0.125 s
Velocity is wavelength times frequency.
v = λf = (0.40 m) (8 Hz) = 3.2 m/s
The wave travels 3.2 meters every second.
Answer:
cross out the false piece in blue and write the true piece in red
Lungs is what helps u breath
Solution:
With reference to Fig. 1
Let 'x' be the distance from the wall
Then for 
DAC:
⇒ 
Now for the BAC:
⇒ 
Now, differentiating w.r.t x:
![\frac{d\theta }{dx} = \frac{d}{dx}[tan^{-1} \frac{d + h}{x} - tan^{-1} \frac{d}{x}]](https://tex.z-dn.net/?f=%5Cfrac%7Bd%5Ctheta%20%7D%7Bdx%7D%20%3D%20%5Cfrac%7Bd%7D%7Bdx%7D%5Btan%5E%7B-1%7D%20%5Cfrac%7Bd%20%2B%20h%7D%7Bx%7D%20-%20%20tan%5E%7B-1%7D%20%5Cfrac%7Bd%7D%7Bx%7D%5D)
For maximum angle, 
= 0
Now,
0 = [/tex]\frac{d}{dx}[tan^{-1} \frac{d + h}{x} - tan^{-1} \frac{d}{x}][/tex]
0 = 
After solving the above eqn, we get
x = 
The observer should stand at a distance equal to x =
