Answer:
work 24.31 ft³/in²
Explanation:
The work in thermodynamic processes is given by a relationship between pressure changes and volume differences as follows:
W = - 
In this exercise they give the pressure ratio P = 23.75 -7.5 V, so we can evaluate the integral between points two V1 = 2.5 ft3 and V2 = 0.5 ft3
W = - [23.75 V -7.5 V² / 2]
W = - [23.75 (0.5 -2.5) - 7.5 (0.5² - 2.5²) / 2]
W = - [-47.5 + 23.19] BTU
W = 24.31 ft3 / in2 = 24.31 BTU
Note that the work is positive since work is done on the gas to compress it.
To solve this problem we will use the two principles that are visible according to the phenomena described in the problem: Heat transfer by conductivity and Heat transfer by convection.
This thermal transfer will be equivalent and with it we can find the value asked.
<em>Note: We will assume that the temperature value at the plate surface is: 60 ° C (For the given value of 650 50)</em>
For Thermal Transfer by Conduction
Where,
k = Thermal conductivity
A = Cross-sectional Area
= Temperature of the bottom surface
= Temperature of the top surface
L = Length
Replacing we have that
For Thermal Transfer by Convection
Where,
h = Convection heat transfer coefficient
= Surrounding temperature
A = Surface Area
Replacing we have that
Since the rate of heat transfer by convection is equal to that given by conduction we have to:
It is stated that the typical values of forced convection of gases lies in the range of 
. The obtained value is reasonable for forced convection of air.
Answer:
The reading of Y is -10°.
Explanation:
For scale X, the ice point is 40° and steam point is 120°.
Difference between the two extremes for scales X = 120 - 40 = 80
For scale X, the ice point and steam points are -30° and 130° respectively.
Difference between the two extremes for scales X = 130 - (-30) = 160
Comparing both scales:
One unit of scale X = x
One unit of scale Y = y
Scale X has 80 divisions while scale Y has 160
80x = 160y
x = 2y
50° in scale X = 10x + ice point in X scale
10 divisions in Y scale = 20y
Reading of Y scale = ice point of Y + 20y
= -30° + 20°
= -10°
Assume the wooden piece prevents the balloon from rising, is not so heavy as to cause the balloon to descend. and the 15 m/s is horizontal velocity “riding the wind,” That horizontal velocity does not affect the time the wood will take to reach the ground after release. Initial vertical velocity is zero.
s = u t + 1/2 g t^2
s is the height above ground, 300 m.
u is initial vertical velocity, zero.
t is time to reach the ground.
g is acceleration of gravity near Earth, 9.8 m/s^2.
300 m = 0 t + 1/2 (9.8 m/s^2) t^2
300 m = (4.9 m/s^2) t^2
61.22 s^2 = t^2
7.82 seconds = t
