Ch 18: Heat and TemperatureSee all chapters
All Chapters
Ch 01: Units & Vectors
Ch 02: 1D Motion (Kinematics)
Ch 03: 2D Motion (Projectile Motion)
Ch 04: Intro to Forces (Dynamics)
Ch 05: Friction, Inclines, Systems
Ch 06: Centripetal Forces & Gravitation
Ch 07: Work & Energy
Ch 08: Conservation of Energy
Ch 09: Momentum & Impulse
Ch 10: Rotational Kinematics
Ch 11: Rotational Inertia & Energy
Ch 12: Torque & Rotational Dynamics
Ch 13: Rotational Equilibrium
Ch 14: Angular Momentum
Ch 15: Periodic Motion (NEW)
Ch 15: Periodic Motion (Oscillations)
Ch 16: Waves & Sound
Ch 17: Fluid Mechanics
Ch 18: Heat and Temperature
Ch 19: Kinetic Theory of Ideal Gasses
Ch 20: The First Law of Thermodynamics
Ch 21: The Second Law of Thermodynamics
Ch 22: Electric Force & Field; Gauss' Law
Ch 23: Electric Potential
Ch 24: Capacitors & Dielectrics
Ch 25: Resistors & DC Circuits
Ch 26: Magnetic Fields and Forces
Ch 27: Sources of Magnetic Field
Ch 28: Induction and Inductance
Ch 29: Alternating Current
Ch 30: Electromagnetic Waves
Ch 31: Geometric Optics
Ch 32: Wave Optics
Ch 34: Special Relativity
Ch 35: Particle-Wave Duality
Ch 36: Atomic Structure
Ch 37: Nuclear Physics
Ch 38: Quantum Mechanics

Concept #1: Introduction to Heat Transfer

Concept #2: Conduction

Practice: A cubic Styrofoam cooler containing ice on a hot day is shown in the following figure. The thickness of each wall of the cooler is 15 mm, with a side length of 1 m. If it is 40°C outside, how long will 2 kg of ice last in the cooler? Assume that during the melting process, the temperature inside the cooler remains at 0°C and that no heat enters from the bottom of the cooler. Note that the latent heat of fusion for water is 334 kJ/kg and the thermal conductivity of Styrofoam is 0.033 W/mK.

Concept #3: Radiation

Practice: If the intensity of sunlight measured at the Earth’s surface is 1400 W/m2 , what is the surface temperature of the Sun? Treat the Sun like a true blackbody. Note that the distance from the Earth to the Sun is 1.5 x 1011 m and the radius of the Sun is 696 million meters.

Additional Problems
A solid metal sphere has surface area 0.200 m 2 and an emissivity of 0.700. The sphere is maintained at a temperature of 60.0°C and the surroundings are at a temperature of 30.0°C. The sphere's rate of heat loss by radiation is (a) 0.100 W (b) 154 W (c) 97.6 W (d) 43.9 W (e) 30.7 W (f) none of the above answers
A hot reservoir at 50oC is connected to a cold reservoir at -60oC by a cylindrical, thermal conductor. The thermal conductor has a constant radius of 5 cm, but is made up of two different metals. The first portion of the conductor, made of aluminum, is 8 cm long and has a thermal conductivity of 205 W/mK and is in contact with the hot reservoir. The second portion of the conductor, made of brass, is 10 cm long and has a thermal conductivity of 109 W/mK, and is in contact with the cold reservoir. (a) What is the temperature at the junction between the aluminum and brass? (b) What is the rate at which heat is passing through the conductor?
The Sun emits 3.92x1026 W of light. If the temperature of the Sun is 5800 K, what is the radius of the Sun? Treat the Sun as an ideal blackbody.
A spherical blackbody at a temperature of 500 K is placed into 200 mL of 10 oC water. If the temperature of the blackbody is 500 K, and the radius is 10 cm, how long would it take to bring the water to a boil? Assume that the blackbody's temperature is roughly constant during this process, and that it is denser than water.
The process whereby heat flows by means of molecular collisions is referred to as [A] conduction. [B] convection. [C] radiation. [D] inversion. [E] evaporation.
Consider the following statements. A. Heat flows from an object at higher temperature to an object at lower temperature; B. Heat flows from an object with higher thermal energy to one with lower thermal energy C. Heat flows from an object in liquid state to an object in solid state. Which statements are true? 1. B only 2. A only 3. A and C only 4. A and B only 5. None is true. 6. B and C only 7. All are true. 8. C only
The Sun acts like an almost perfect blackbody. If the peak emission from the Sun occurs at around 500 nm, what is the approximate temperature of the Sun?
When a car brakes, a brake pad is pushed firmly against a disk, which allows the wheels to slow down. The effectiveness of brakes is limited by something known as “fade” – a rapid drop in friction. In a typical brake pad, the friction surface should remain below 450°C to prevent fade. For all problems, assume that the air temperature is 23°C. (a) For a brake pad 1.65 cm thick, with an area of 53 cm  2 and a thermal conductivity of 12 W/mK, what is the maximum heat current through the pad that won't cause fade? Assume that the same amount of heat leaks out of the sides of the pad as goes straight through it.         (b) For a disk 1.1 cm thick, with an area of 268 cm  2 and a thermal conductivity of 43.5 W/mK, what is the maximum heat current through the disk that won't cause fade? Assume that the amount of heat leaks out of the sides of the disk as goes straight through it.         (c) For a 2000 kg car going 30 m/s, what is the shortest stopping distance the car can achieve without inducing fade? Assume that the car has 4 uniform brakes. 
A metal rod, with a length of 2 cm and a cross sectional area of 50 cm2, is connected beteween a hot reservoir at 300°C and a cold reservoir at 15°C. If you measure the heat current in the rod to be 1.5 kW, what is the thermal conductivity of the metal used to make the rod?