1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
kobusy [5.1K]
3 years ago
7

To start a great night of doing physics homework, you sit down to pour yourself a good cup of coffee. Your coffee mug has a mass

137 g and a specific heat of 1089 J/kg K. The mug starts out at room temperature (23.8 o C). Your coffee has an initial temperature of 79.8 oC and has the same specific heat as water (4186 J/kg K).
1) Let's say you pour enough coffee into the mug so that the mass of coffee is equal to the mass of the mug. If we assume that no heat is lost to the outside room, once the mug and coffee reach the same temperature, will that temperature be closer to the initial temperature of the coffee or the initial temperature of the mug? (Notice that the mass of the coffee and the mass of the mug are the same.)
2) What is the final temperature of coffee and mug once they come to thermal equilibrium?
Tfinal = ____________ degrees c
3) Now lets assume that instead of the 137 g of coffee, you pour in 225 g of coffee. What is the final temperature of the coffee and mug? (Again, assume that you loose no heat to the outside.)
Tfinal = ____________ degrees c
4) Now lets say that along with the 225 g of coffee, you pour in 11.7 g of cream in your mug. The cream has an initial temperature of 5.2 oC and also has the same specific heat as water. What is the final temperature of the coffee, cream and mug? (Again, assume that you loose no heat to the outside.)
Tfinal = _____________ degrees c
Physics
1 answer:
astra-53 [7]3 years ago
6 0

Answer:

1) The temperature will be closer to water

2) T = 68.239°C

3) T = 72.142°C

4) T = 69.266 °C

Explanation:

1)

The temperature will be closer to water because  the heat capacity of water > heat capacity of coffee.

2)

137(1.089)(T - 23.8) = 137(4.186)(79.8 - T)

⇒(1.089)(T - 23.8) = (4.186)(79.8 - T)

⇒1.089 T - 25.9182 = 334.0428 - 4.186 T

⇒1.089 T +  4.186 T = 334.0428 + 25.9182

⇒5.275 T = 359.961

⇒ T = 68.239°C

3)

137(1.089)(T - 23.8) = 225(4.186)(79.8 - T)

⇒(149.193)(T - 23.8) = (941.85)(79.8 - T)

⇒149.193 T - 3550.7934 = 75159.63 - 941.85 T

⇒149.193 T +  941.85 T = 75159.63  + 3550.7934

⇒1091.043 T = 78710.4234

⇒ T = 72.142°C

4)

137(1.089)(T - 23.8) + 11.7(4.186)(T - 5.2)= 225(4.186)(79.8 - T)

⇒(149.193)(T - 23.8) + 48.9762(T - 5.2) = (941.85)(79.8 - T)

⇒149.193 T - 3550.7934  + 48.9762 T - 254.67624= 75159.63 - 941.85 T

⇒149.193 T +  941.85 T + 48.9762 T = 75159.63  + 3550.7934 + 254.67624

⇒1091.043 T + 48.9762 T = 78710.4234 + 254.67624

⇒1140.0192 T = 78965.09964

⇒ T = 69.266 °C

You might be interested in
which of this is not example of simple machine? A) a crowbar,B)a knife,C)a bicycle,D)a wheelchair ramp
DaniilM [7]
B. Knife HOpe this helps :3
3 0
3 years ago
Describe the valence electrons in nitrogen and how it could bond to other atoms?
Gekata [30.6K]

Answer:

Each nitrogen molecule consists of two atoms of nitrogen that are bonded by a triple covalent bond. This is because each nitrogen atom has 5 valence electrons. Each atom can complete its octet by sharing three electrons.

I hope this helps!

4 0
3 years ago
A drag racing car with a weight of 1600 lbf attains a speed of 270 mph in a quarter-mile race. Immediately after passing the tim
Kaylis [27]

Answer:

15.065ft

Explanation:

To solve this problem it is necessary to consider the aerodynamic concepts related to the Drag Force.

By definition the drag force is expressed as:

F_D = -\frac{1}{2}\rho V^2 C_d A

Where

\rho is the density of the flow

V = Velocity

C_d= Drag coefficient

A = Area

For a Car is defined the drag coefficient as 0.3, while the density of air in normal conditions is 1.21kg/m^3

For second Newton's Law the Force is also defined as,

F=ma=m\frac{dV}{dt}

Equating both equations we have:

m\frac{dV}{dt}=-\frac{1}{2}\rho V^2 C_d A

m(dV)=-\frac{1}{2}\rho C_d A (dt)

\frac{1}{V^2 }(dV)=-\frac{1}{2m}\rho C_d A (dt)

Integrating

\int \frac{1}{V^2 }(dV)= - \int\frac{1}{2m}\rho C_d A (dt)

-\frac{1}{V}\big|^{V_f}_{V_i}=\frac{1}{2m}(\rho)C_d (\pi r^2) \Delta t

Here,

V_f = 60mph = 26.82m/s

V_i = 120.7m/s

m= 1600lbf = 725.747Kg

\rho = 1.21 kg/m^3

C_d = 0.3

\Delta t=7s

Replacing:

\frac{-1}{26.82}+\frac{1}{120.7} = \frac{1}{2(725.747)}(1.21)(0.3)(\pi r^2) (7)

-0.029 = -5.4997r^2

r = 2.2963m

d= r*2 = 4.592m \approx 15.065ft

4 0
3 years ago
7. A beam of light converges at a point P. Now a lens is placed in the path of the convergent
Rudiy27

Answer:

Lens at a distance = 7.5 cm

Lens at a distance = 6.86 cm  (Approx)

Explanation:

Given:

Object distance u = 12 cm

a) Focal length = 20 cm

b) Focal length = 16 cm

Computation:

a. 1/v = 1/u + 1/f

1/v = 1/20 + 1/12

v = 7.5 cm

Lens at a distance = 7.5 cm

b.  1/v = 1/u + 1/f

1/v = 1/16 + 1/12

v = 6.86 cm  (Approx)

Lens at a distance = 6.86 cm  (Approx)

5 0
3 years ago
What happens to the mechanical energy of an apple as it falls from a tree?
Vikentia [17]

Answer:

When the apple falls from the tree, it has some gravitational potential energy due to its height. Now, When it starts falling, the Gravitation Potential energy will starts converting into the Kinetic Energy. When the apple is about to strikes the ground, the Gravitational Potential energy have been converted into the Kinetic Energy.

Explanation:

4 0
2 years ago
Other questions:
  • Ikes teacher tells him that this process has caused each strip of tape to gain a negative electric charge. What could ike do nex
    6·1 answer
  • What frequency is received by a stationary mouse just before being dispatched by a hawk flying at it at 24.7 m/s and emitting a
    6·1 answer
  • When a person plucks a guitar string, the number of half wavelengths that fit into the length of the string determines the _____
    10·1 answer
  • In Paragraph 3 of this passage, what clues help you know the meaning of the word
    8·1 answer
  • What were clark's independent and dependent variables
    7·2 answers
  • Which of the 3 states of matter is easier to increase the temperature by one degree; in a liquid, in a solid, or in a gas?
    11·1 answer
  • Density of water is 1000 kg/m^3. What will be the volume of 35000 kg water?
    5·1 answer
  • The owner of a van installs a rear-window lens that has a focal length of -0.304 m. When the owner looks out through the lens at
    7·1 answer
  • Lindsay is planning a flight from St. Catharines to Hamilton, which lies due west of St. Catharines. Her aircraft flies at a spe
    11·2 answers
  • A convex mirror has a focal length of -13.0 cm. When you place a 6.00 cm tall pencil 60.0 cm in front of that mirror, what is th
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!