Thermal Concepts

Thermal energy occurs when two objects in contact have different …

• temperatures.

• total kinetic energy of the molecules.

• intermolecular potential energy.

• internal energy.

Energy of an object or system that includes kinetic, gravitational potential and elastic potential is called …

• Mechanical energy.

• Thermal energy.

• Internal energy.

• Work energy.

Energy of the molecules of an object which is the sum of random kinetic energy and intermolecular potential energy is called …

• Mechanical energy.

• Thermal energy.

• Internal energy.

• Work energy.

The temperature at night in Beijing in December is around …

• 5 °C

• -6 K

• 267 K

• 278 °C

Some chefs prefer copper cooking pots over those of stainless steel.

c _copper = 385 J kg^-1 K^-1

c _steel = 500 J kg^-1 K^-1

Which will heat up quicker over the same flame?

• The copper one.

• The stainless steel one.

• It depends on the mass of each pot.

• It depends on the temperature of the flame.

Some chefs prefer copper cooking pots over stainless steel.

c _copper = 385 J kg^-1 K^-1

c _steel = 500 J kg^-1 K^-1

For two pots of the same mass and starting temperature, which will stay warmer longer once the stove is turned off?

• The copper one.

• The stainless steel one.

• It depends on the height of the chef's hat.

• It depends on the color of the stove.

A 5.0 kg iron cannon ball is dropped from a height of 20. m. When it strikes the ground, 65% of its kinetic energy is transformed into random kinetic energy of the molecules. Calculate the temperature change for the cannon ball.

c_iron = 450 J kg^-1 K^-1

• 0.044 K

• 0.44 K

• 0.28 K

• 1.4 K

The handle of a cooking pot will most likely become hot when cooking because of a method of thermal energy called…

• conduction.

• convection.

• convention.

• radiation.

Temperature is a measure of …

• the average kinetic energy of the object.

• the kinetic energy of the molecules.

• the average potential energy of the molecules.

• the average kinetic energy of the molecules.

Intermolecular potential energy is …

• due to the random motion of the molecules.

• due to the forces between molecules.

• a portion of the thermal energy of an object.

• what changes when temperature of an object changes.