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: Linear Thermal Expansion

Practice: Train tracks are composed of 10 m segments of steel rails. If the temperature outside is 30°C on average, and the temperature in the factory that produces the rails is 20°C, what length must the steel rails be produced at so that the fit perfectly end-to-end when laid outside? The linear expansion coefficient of steel is 1.2 x 10-5 K-1.

Concept #2: Volume Thermal Expansion

Practice: A cube and a sphere are made of the same material. Initially, the sphere just fits inside of the cube; that is, the length of the cube is twice the radius. If the sphere and cube are both heated up some amount, will the sphere still fit inside the cube?

Additional Problems
When constructing a railroad, two connecting rails need to be given a small separation, to allow for expansion during the summer months. If the beams are made of steel in a factory at 23oC at a length of 3 m, and they can be expected to heat up to temperatures of 50oC, what should the spacing between steel beams be? Consider the coefficient of linear thermal expansion of steel to be 12x10-6 K-1.
A circular hole in a flat copper plate has diameter 0.030 m at T = 40°C. If the copper plate is heated to 60°C, the diameter of the hole (a) increases (b) decreases (c) stays the same
A rod of unknown material is 1.2 m long at 10 oC and is found to increase to a length of 1.3 m at 350oC. What is the linear expansion coefficient of this unknown material?
A uniform density sphere of mass ms, initial radius r0, specific heat c and coefficient of linear expansion α is at rest at the bottom of a bucket of water with density pω. A heater inside the sphere is turned on remotely and generates a heat Q. Since the sphere is well insulated, no heat is transferred to the water; however the heat causes the sphere to expand and rise to the surface. a) What is the buoyant force on the sphere before the heater is turned on? (Give your answer in terms of the given quantities and check units.) b) How much heat, Q, is required to cause the sphere to float to the surface such that half of the sphere is exposed to air? (Give your answer in terms of given quantities and check units.)
Cobalt has a coefficient of linear thermal expansion of 12x10-6 K-1. If a sample of Cobalt starts at 20oC, what temperature does it need to be increased to to increase its length by 0.15%?