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
melisa1 [442]
3 years ago
15

Rubbing your hands together warms them by converting work into thermal energy. If a woman rubs her hands back and forth for a to

tal of 18 rubs, at a distance of 7.16 cm per rub, and with an average frictional force of 48 N, what is the temperature increase? The mass of tissues warmed is only 0.1 kg, mostly in the palms and fingers.
Physics
1 answer:
KATRIN_1 [288]3 years ago
6 0

Answer:

0.178 °C

Explanation:

Given:

The frictional force, F = 48 N

Number of rubs, n = 18

Distance covered per rub, d = 7.16 cm = 0.0716 m

Total distance covered in 18 rubs, D = 0.0716 × 18 = 1.288 m

mass of the tissues warmed, m = 0.1 kg

Now,

Work done, W = Force × Displacement

W = 48 × 1.288 = 61.8624 J

Now,

Work done is the change in heat

W = ΔQ = 61.8624 J

also,

ΔQ = mCΔT

where, C is the specific heat

for human tissue, C = 3470 J/kg°C

thus,

61.8624 J = 0.1 × 3470 × ΔT

or

ΔT = 0.178 °C

Hence, the change in temperature is 0.178 °C

You might be interested in
A spring stretches by 0.0208 m when a 3.39-kg object is suspended from its end. How much mass should be attached to this spring
sashaice [31]

Answer:

COMPLETE QUESTION

A spring stretches by 0.018 m when a 2.8-kg object is suspended from its end. How much mass should be attached to this spring so that its frequency of vibration is f = 3.0 Hz?

Explanation:

Given that,

Extension of spring

x = 0.0208m

Mass attached m = 3.39kg

Additional mass to have a frequency f

Let the additional mass be m

Using Hooke's law

F= kx

Where F = W = mg = 3.39 ×9.81

F = 33.26N

Then,

F = kx

k = F/x

k = 33.26/0.0208

k = 1598.84 N/m

The frequency is given as

f = ½π√k/m

Make m subject of formula

f² = ¼π² •(k/m

4π²f² = k/m

Then, m4π²f² = k

So, m = k/(4π²f²)

So, this is the general formula,

Then let use the frequency above

f = 3Hz

m = 1598.84/(4×π²×3²)

m = 4.5 kg

4 0
3 years ago
The formula $F = \frac{9}{5} C + 32$ can be used to convert temperatures between degrees Fahrenheit ($F$) and degrees Celsius ($
slamgirl [31]

Answer:

-30° C

Explanation:

Data provided in the problem:

The formula for conversion as:

F  = (9/5)C + 32

Now,

for the values of F = -22 , C = ?

Substituting the value of F in the above formula, we get

-22 = (9/5)C + 32

or

-22 - 32 = (9/5)C

or

(9/5)C = - 54

or

C = - 54 × (5/9)

or

C = - 30 °

Hence, -22 Fahrenheit equals to -30°C

7 0
2 years ago
suggest an experiment to prove that the rate of evaporation of a liquid depends on its surface area vapour already present in su
gulaghasi [49]
That's two different things it depends on:

-- surface area exposed to the air
AND
-- vapor already present in the surrounding air.

Here's what I have in mind for an experiment to show those two dependencies:

-- a closed box with a wall down the middle, separating it into two closed sections;

-- a little round hole in the east outer wall, another one in the west outer wall,
and another one in the wall between the sections;
So that if you wanted to, you could carefully stick a soda straw straight into one side,
through one section, through the wall, through the other section, and out the other wall.

-- a tiny fan that blows air through a tube into the hole in one outer wall.

<u>Experiment A:</u>

-- Pour 1 ounce of water into a narrow dish, with a small surface area.
-- Set the dish in the second section of the box ... the one the air passes through
just before it leaves the box.
-- Start the fan.
-- Count the amount of time it takes for the 1 ounce of water to completely evaporate.
=============================
-- Pour 1 ounce of water into a wide dish, with a large surface area.
-- Set the dish in the second section of the box ... the one the air passes through
just before it leaves the box.
-- Start the fan.
-- Count the amount of time it takes for the 1 ounce of water to completely evaporate.
=============================
<span><em>Show that the 1 ounce of water evaporated faster </em>
<em>when it had more surface area.</em></span>
============================================
============================================

<u>Experiment B:</u>

-- Again, pour 1 ounce of water into the wide dish with the large surface area.
-- Again, set the dish in the second half of the box ... the one the air passes
through just before it leaves the box.
-- This time, place another wide dish full of water in the <em>first section </em>of the box,
so that the air has to pass over it before it gets through the wall to the wide dish
in the second section.  Now, the air that's evaporating water from the dish in the
second section already has vapor in it before it does the job.
-- Start the fan.
-- Count the amount of time it takes for the 1 ounce of water to completely evaporate.
==========================================
<em>Show that it took longer to evaporate when the air </em>
<em>blowing over it was already loaded with vapor.</em>
==========================================
6 0
3 years ago
Becky has a younger sister. If the sister was half Becky's age when Becky was 6, and Becky is now 70, how old is Becky's sister?
rjkz [21]

Answer:

67

Explanation:

8 0
3 years ago
Read 2 more answers
A sample of a diatomic ideal gas has pressure P and volume V. When the gas is warmed, its pressure triples and its volume double
Andreyy89

Answer:

Amount of  Energy transferred =8.5PV

Explanation:

Given:

Initial volume=V

Initial pressure=P

Final volume=2V

Final pressure=3P

Now w know that the Energy transferred in constant pressure pressure is given by

E_1=nc_pdT\\\\E_1=n\times\dfrac{7R}{2}dT\\E_1=3.5(nRdT)\\E_1=3.5(V(2P-P))\\E_1=3.5PV

Now the Energy transferred in constant volume process is given by

E_2=nc_vdT\\\\E_2=n\times\dfrac{5R}{2}dT\\E_1=2.5(nRdT)\\E_1=2.5(V(3V-V))\\E_1=5PV

The total Energy transferred is given by

E_{total}=E_1+E_2\\E{total}=3.5PV+5PV\\=8.5PV

3 0
3 years ago
Read 2 more answers
Other questions:
  • An ac generator consists of a coil with 40 turns of wire, each with an area of 0.06 m2. The coil rotates in a uniform magnetic f
    13·1 answer
  • Permeability is the condition of being capable of having materials flow into and out of a membrane. The permeability of a cell m
    6·2 answers
  • Slick Willy is in traffic court (again) contesting a $50.00 ticket for running a red light. "You see, your Honor, as I was appro
    10·2 answers
  • A sample of metallic frewium weighs 185N on a spring scale in air. When immersed in pure water, the frewium pulls on the scale w
    14·1 answer
  • 4. A graduated cylinder is used<br>to measure<br>a. volume<br>b. weight<br>d. inertia<br>c. mass​
    11·1 answer
  • Student A walks up a 10 meter staircase. Student B runs up the same staircase in less
    14·1 answer
  • A car accelerates from rest at 1.0 m/s2 for 20.0 second along a straight road. It then moves at a constant speed for half an hou
    15·1 answer
  • What is formed when two or more
    11·2 answers
  • A spring stretches 2 meters when a 12 N force is acting on it. What is the spring constant (k)? 10 N/m 0.17 N/m 2 N/m 6 N/m
    13·1 answer
  • What level of education is required to obtain a position as a insurance billing specialist ?
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!