<< Chapter < Page Chapter >> Page >

Conceptual questions

What three factors affect the heat transfer that is necessary to change an object’s temperature?

Got questions? Get instant answers now!

The brakes in a car increase in temperature by Δ T size 12{ΔT} {} when bringing the car to rest from a speed v size 12{v} {} . How much greater would Δ T size 12{ΔT} {} be if the car initially had twice the speed? You may assume the car to stop sufficiently fast so that no heat transfers out of the brakes.

Got questions? Get instant answers now!


On a hot day, the temperature of an 80,000-L swimming pool increases by 1 . 50ºC size 12{1 "." "50"°C} {} . What is the net heat transfer during this heating? Ignore any complications, such as loss of water by evaporation.

5 . 02 × 10 8 J size 12{5 "." "02" times "10" rSup { size 8{8} } `J} {}
Got questions? Get instant answers now!

Show that 1 cal/g ºC = 1 kcal/kg ºC size 12{1`"cal/g" cdot °C=1`"kcal/kg" cdot °C} {} .

Got questions? Get instant answers now!

To sterilize a 50.0-g glass baby bottle, we must raise its temperature from 22 . 0 ºC to 95 . C . How much heat transfer is required?

3. 07 × 10 3 J
Got questions? Get instant answers now!

The same heat transfer into identical masses of different substances produces different temperature changes. Calculate the final temperature when 1.00 kcal of heat transfers into 1.00 kg of the following, originally at 20 . C : (a) water; (b) concrete; (c) steel; and (d) mercury.

Got questions? Get instant answers now!

Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a total of 20 rubs, at a distance of 7.50 cm per rub, and with an average frictional force of 40.0 N, what is the temperature increase? The mass of tissues warmed is only 0.100 kg, mostly in the palms and fingers.

0 . 171º C size 12{0 "." "171"°C} {}
Got questions? Get instant answers now!

A 0.250-kg block of a pure material is heated from 20 . C size 12{"20" "." 0°C} {} to 65 . C size 12{"65" "." 0°C} {} by the addition of 4.35 kJ of energy. Calculate its specific heat and identify the substance of which it is most likely composed.

Got questions? Get instant answers now!

Suppose identical amounts of heat transfer into different masses of copper and water, causing identical changes in temperature. What is the ratio of the mass of copper to water?


Got questions? Get instant answers now!

(a) The number of kilocalories in food is determined by calorimetry techniques in which the food is burned and the amount of heat transfer is measured. How many kilocalories per gram are there in a 5.00-g peanut if the energy from burning it is transferred to 0.500 kg of water held in a 0.100-kg aluminum cup, causing a 54 . C temperature increase? (b) Compare your answer to labeling information found on a package of peanuts and comment on whether the values are consistent.

Got questions? Get instant answers now!

Following vigorous exercise, the body temperature of an 80.0-kg person is 40 . C . At what rate in watts must the person transfer thermal energy to reduce the the body temperature to 37 . C in 30.0 min, assuming the body continues to produce energy at the rate of 150 W? 1 watt = 1 joule/second or 1 W = 1 J/s .

617 W

Got questions? Get instant answers now!

Even when shut down after a period of normal use, a large commercial nuclear reactor transfers thermal energy at the rate of 150 MW by the radioactive decay of fission products. This heat transfer causes a rapid increase in temperature if the cooling system fails ( 1 watt = 1 joule/second or 1 W = 1 J/s and 1 MW = 1 megawatt ) . (a) Calculate the rate of temperature increase in degrees Celsius per second ( ºC/s ) if the mass of the reactor core is 1 . 60 × 10 5 kg and it has an average specific heat of 0.3349 kJ/kgº C . (b) How long would it take to obtain a temperature increase of 2000º C , which could cause some metals holding the radioactive materials to melt? (The initial rate of temperature increase would be greater than that calculated here because the heat transfer is concentrated in a smaller mass. Later, however, the temperature increase would slow down because the 5 × 10 5 -kg steel containment vessel would also begin to heat up.)

Got questions? Get instant answers now!

The figure shows a view from above of a radioactive spent fuel pool inside a nuclear power plant.
Radioactive spent-fuel pool at a nuclear power plant. Spent fuel stays hot for a long time. (credit: U.S. Department of Energy)

Questions & Answers

what is airflow
Godswill Reply
derivative of first differential equation
Haruna Reply
why static friction is greater than Kinetic friction
Ali Reply
draw magnetic field pattern for two wire carrying current in the same direction
Ven Reply
An American traveler in New Zealand carries a transformer to convert New Zealand’s standard 240 V to 120 V so that she can use some small appliances on her trip.
nkombo Reply
What is the ratio of turns in the primary and secondary coils of her transformer?
How electric lines and equipotential surface are mutually perpendicular?
Abid Reply
The potential difference between any two points on the surface is zero that implies È.Ŕ=0, Where R is the distance between two different points &E= Electric field intensity. From which we have cos þ =0, where þ is the angle between the directions of field and distance line, as E andR are zero. Thus
sorry..E and R are non zero...
By how much leeway (both percentage and mass) would you have in the selection of the mass of the object in the previous problem if you did not wish the new period to be greater than 2.01 s or less than 1.99 s?
Elene Reply
what Is linear momentum
Victoria Reply
why no diagrams
Blessing Reply
Describe an experiment to determine short half life
Tyson Reply
what is science
Kenedy Reply
it's a natural phenomena
please can someone help me with explanations of wave
there are seven basic type of wave radio waves, gyamma rays (nuclear energy), microwave,etc you can also search 🔍 on Google :-)
A 20MH coil has a resistance of 50 ohms and us connected in series with a capacitor to a 520MV supply
Musa Reply
what is physics
Caya Reply
it is the science which we used in our daily life
Physics is the branch of science that deals with the study of matter and the interactions it undergoes with energy
it is branch of science which deals with study of happening in the human life
A 20MH coil has a resistance of 50 ohms and is connected in series with a capacitor to a 250MV supply if the circuit is to resonate at 100KHZ, Determine 1: the capacitance of the capacitor 2: the working voltage of the circuit, given that pie =3.142
Physics is the branch of science that deals with the study of matter and the interactions it undergoes with energy
Heat is transfered by thermal contact but if it is transfered by conduction or radiation, is it possible to reach in thermal equilibrium?
Eden Reply
Yes, It is possible by conduction if Surface is Adiabatic
Yeah true ilwith d help of Adiabatic
what are the fundamentals qualities
Magret Reply
what is physic3
what is physic
Physics? Is a branch of science dealing with matter in relation to energy.
Physic... Is a purging medicine, which stimulates evacuation of the bowels.
are you asking for qualities or quantities?
fundamental quantities are, length , mass, time, current, luminous intensity, amount of substance, thermodynamic temperature.
fundamental quantities are quantities that are independent of others and cannot be define in terms of other quantities there is nothing like Qualities we have only fundamental quantities which includes; length,mass,time, electric current, luminous density, temperature, amount of substance etc
Practice Key Terms 1

Get the best College physics course in your pocket!

Source:  OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'College physics' conversation and receive update notifications?