Consider an acrylic sheet of thickness L = 5 mm that is used to coat a hot, isothermal metal substrate at Th = 300°C. The proper
ties of the acrylic are rho = 1990 kg/m3, c = 1470 J/kg · K, and k = 0.21 W/m · K. Neglecting the thermal contact resistance between the acrylic and the metal substrate, determine how long it will take for the insulated back side of the acrylic to reach its softening temperature, Tsoft = 90°C. The initial acrylic temperature is Ti = 20°C.
1 answer:
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Answer:
719
Explanation:
Conversion
1 picometer (pm) is equivalent to meter
1 micrometer is equivalent to meter
To find the number of layers, we divide the overal leaf thickness by the thickness of one atom hence dividing tex]0.125 × 10^{-6}[/tex] meter by meter we get that the number of sheets will be as follows
Therefore, they are approximately 719 sheets
Answer:
a) Average speed = 200 Km/hr
b) Average velocity = 0 m/s
c) Total distance = 800 Km
d) Total displacement = 0 Km
Explanation:
a) Let the speed of the plane from Addis Ababa to Gamble be represented by , and from Gamble to Addis Ababa by
.
Average speed =
=
=
= 200 Km/hr
=
=
= 200 Km/hr
Average speed =
= 200 Km/hr
b) Velocity =
Average velocity =
Since the plane flies from Addis Ababa to Gamble, then back to Addis Ababa, its total displacement is zero.
So that,
Average velocity = 0 m/s
c) Total distance = 400 Km + 400 Km
= 800 Km
d) Total displacement = 400 Km + (-400 Km)
= 0 Km