A gas is trapped in a container at a pressure of 20 x 105 N/m2. How much force d

Question

A gas is trapped in a container at a pressure of 20 x 105 N/m2. How much
force does the gas exert on the circular piston of the container if its radius is 4 cm?

answer is 10100 N


Two kg of ice at 0? C is placed in a Styrofoam cooler with a total surface area of
1.5 m2 and walls with a 0.015 m thickness. If after 12 hours in a 30? C
environment, 0.5 kg of the ice has melted, calculate the thermal conductivity of the
cooler.

0.00129 J/s m degrees C


What is the maximum efficiency of a heat engine that operates between
temperatures of 1500 K in the firing chamber and 500 K in the exhaust chamber?

66.7%





I provided all the answers I just want a very detailed step by step explanation please!!!

Explanation / Answer

1. force = pressure * area
= 20* 10^5 * (pi*r^2) where r = 0.04m
= 10053.09N
= 10100N (rounding off)

where q = rate of heat transfer

k = thermal conductivity

Latent heat of fusion of water = 334 KJ/Kg so for 0.5 kg of ice heat released = 117 KJ

q = 167KJ/ (12*3600) KJ/sec

q = 3.8657 J/sec

now A= 1.5m2

thickness = 0.015m

so T/X = -30/0.015 = 2000degree/meter

so k = q/(A*2000))

k = 1.288 *10^-3 J/s m degrees C

3. maximum efficiency = 1 -Tmin/Tmax

= 1 - 500/1500

= 0.667

= 66.7%

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.