If you mix food in a blender, the electric motor does work on the system, which consists of the food inside the container. This work can noticeably warm up the food. Suppose the blender motor runs at a power of 250 W for 40 s. During this time, 2000 J of heat flow from the now-warmer food to its cooler surroundings. Match the answers with questions. (Hint: Example 11.12) v W- work done on the system (food) A. 2000 J v Q- Heat into or out of the system (food) B. 8000 J v AEth - Change in thermal energy of the system (food) C. OJ D. -10,000 J E. -8000 J F. -2000 J G. 10,000 J

When you skid to a stop on a bicycle, you can significantly heat the small patch of tire that rubs against the road surface. Suppose a person skids to a stop by hitting the brake on the back tire, which supports half of the combined mass (which is 75kg) of the bike and rider, leaving a skid mark that is 40 cm long. Assume a coefficient of kinetic friction of 0.80. How much thermal energy is deposited on the tire and road surface?

The rate at which a resting person converts food energy is called one’s basal metabolic rate (BMR). Assume that the resulting internal energy leaves a person’s body by radiation and convection of dry air. When you jog, most of the food energy you burn above your BMR becomes internalenergy that would raise your body temperature if it were not eliminated. Assume that evaporation of perspiration is the mechanism for eliminating this energy. Suppose a person is jogging for “maximum fat burning,” converting food energy at the rate 400 kcal/h above his BMR, and putting out energy by work at the rate 60.0 W. Assume that the heat of evaporation of water at body temperature is equal to its heat of vaporization at 100°C. (a) Determine the hourly rate at which water must evaporate from his skin. (b) When you metabolize fat, the hydrogen atoms in the fat molecule are transferred to oxygen to form water. Assume that metabolism of 1.00 g of fat generates 9.00 kcal of energy and produces 1.00 g of…

A rigid tank contains a hot fluid that is cooled while being stirred by a paddle wheel. Initially, the internal energy of the fluid is 800 kJ. During the cooling process, the fluid loses 500 kJ of heat, and the paddle wheel does 100 kJ of work on the fluid. Determine the final internal energy of the fluid. Neglect the energy stored in the paddle wheel.

After you drive for a while your tires will gain some energy via friction and heat up. If the air inside the tires absorbs 150 Joules of energy by heat, and does 100 Joules of work by expanding and lifting your car a fraction of a millimeter, what is the net change in the internal energy of the air inside the tires? (Hint: Use the first law of thermodynamics) 100 Joules 50 Joules 250 Joules 150 Joules

A certain car has 14 L of liquid coolant circulating at a temperature of 95 degrees Celsius through the engine’s cooling system. Assume that, in this normal condition, the coolant completely fills the 3.5 L volume of the aluminum radiator and the 10.5 L internal cavities within the aluminum engine. When a car overheats, the radiator, engine, and coolant expand and a small reservoir connected to the radiator catches any resultant coolant overflow. Estimate how much coolant overflows to the reservoir if the system goes from 95 degrees Celsius to 106 degrees Celsius. Model the radiator and engine as hollow shells of aluminum. The coefficient of volume expansion for coolant is 410x10^-6 degrees Celsius

The urban heat island effect is often strongest at night when temperatures would typically drop.  What does this indicate about energy transfer and the material used in the building? (a) The material in buildings releases more energy at night than it absorbs during the day (b) The material in buildings absorbs a lot of energy during the day and when it gets colder at night the energy is released back into the cooler air. (c) The material in buildings absorbs energy during the day and releases it because the temperature of the buildings is lower than the cooler air (d) The material in buildings releases a lot of energy into the hot air during the day so at night all of the energy is still there

During a chemistry lab, you take a 0.4 kg sample of ice and put it in a beaker with a thermometer. You then place the beaker with the ice on 0 the temperature of the ice is -18 = a hot plate, and turn on the hot plate. This hot plate adds heat to the ice at a rate of 330 W. At time t °C. Because of the large heat capacity of water and ice, you may assume in this problem that all the heat goes into the sample of ice, and that we can ignore the amount of heat going into the beaker and thermometer. Also assume no heat escapes from the system. Some useful values: ● Specific heat of water: C = Specific heat of ice: Ci = 2100 J/kg K • Latent heat of fusion: L = 334 000 J/kg ● 4200 J/kg K = 1a) At what time does the ice reach a temperature of -3.5°C? answer= units? 1b) At what time has all the ice melted? answer= units? Check your answer Check your answer 1c) After the ice has completely melted, we're left with 0.4 kg of water. Check your answer answer= units? not yet solved not yet solved…

A sample of a monoatomic ideal gas has a pressure of p and volume V. When the gas is warmed, it’s pressure triples and volume triples. This warming process includes two steps, the first at constant pressure and the second at constant volume. Determine the amount of energy transferred to the gas by heat.