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
Ivanshal [37]
3 years ago
13

A rough surface for infrared waves may be polished for

Physics
1 answer:
zloy xaker [14]3 years ago
7 0

Answer:

Radio Waves

Explanation:

You might be interested in
Plz someone help me Asap​
-Dominant- [34]

Answer:

all I know is C

are there more questions? anyone?

-KARL IS STOOPID

Explanation:

6 0
3 years ago
A rock is dropped from the top of a tall tower. Half a second later another rock, twice as massive as the first, is dropped. Ign
Gemiola [76]
B- the acceleration is greater for the more massive rock
5 0
2 years ago
Read 2 more answers
A girl is sledding down a slope that is inclined at 30º with respect to the horizontal. The wind is aiding the motion by providi
OleMash [197]

Answer:

The sled required 9.96 s to travel down the slope.

Explanation:

Please, see the figure for a description of the problem. In red are the x and y-components of the gravity force (Fg). Since the y-component of Fg (Fgy) is of equal magnitude as Fn but in the opposite direction, both forces get canceled.

Then, the forces that cause the acceleration of the sled are the force of the wind (Fw), the friction force (Ff) and the x-component of the gravity force (Fgx).

The sum of all these forces make the sled move. Finding the resulting force will allow us to find the acceleration of the sled and, with it, we can find the time the sled travel.

The magnitude of the friction force is calculated as follows:

Ff = μ · Fn

where :

μ = coefficient of kinetic friction

Fn =  normal force

The normal force has the same magnitude as the y-component of the gravity force:

Fgy = Fg · cos 30º = m · g · cos 30º

Where

m = mass

g = acceleration due to gravity

Then:

Fgy = m · g · cos 30º = 87.7 kg · 9.8 m/s² · cos 30º

Fgy = 744 N

Then, the magnitude of Fn is also 744 N and the friction force will be:

Ff = μ · Fn = 0.151 · 744 N = 112 N

The x-component of Fg, Fgx, is calculated as follows:

Fgx = Fg · sin 30º = m·g · sin 30º = 87.7 kg · 9.8 m/s² · sin 30º = 430 N

The resulting force, Fr, will be the sum of all these forces:

Fw + Fgx - Ff = Fr

(Notice that forces are vectors and the direction of the friction force is opposite to the other forces, then, it has to be of opposite sign).

Fr = 161 N + 430 N - 112 N = 479 N

With this resulting force, we can calculate the acceleration of the sled:

F = m·a

where:

F = force

m = mass of the object

a = acceleration

Then:

F/m = a

a = 479N/87.7 kg = 5.46 m/s²

The equation for the position of an accelerated object moving in a straight line is as follows:

x = x0 + v0 · t + 1/2 · a · t²

where:

x = position at time t

x0 = initial position

v0 = initial velocity

t = time

a = acceleration

Since the sled starts from rest and the origin of the reference system is located where the sled starts sliding, x0 and v0 = 0.

x = 1/2· a ·t²

Let´s find the time at which the position of the sled is 271 m:

271 m = 1/2 · 5.46 m/s² · t²

2 · 271 m / 5.46 m/s² = t²

<u>t = 9.96 s </u>

The sled required almost 10 s to travel down the slope.

8 0
3 years ago
A carbon resistor is to be used as a thermometer. On a winter day when the temperature is 4.00°C, the resistance of the carbon r
dusya [7]

Answer:

28 degree C

Explanation:

We are given that

T_1=4.00^{\circ}

R_1=217.7 \Ohm

R_2=215.1\Ohm

\alpha=-5.00\times 10^{-4}C^{-1}

We have to find the temperature on a spring day when resistance is 215.1 ohm.

We know that

\alpha(T_2-T_1)=\frac{R_2}{R_2}-1

Using the formula

-5.00\times 10^{-4}(T_2-4)=\frac{215.1}{217.7}-1

-5\times 10^{-4}(T_2-4)=0.988-1=-0.012

T_2-4=\frac{0.012}{5\times 10^{-4}}=24

T_2=24+4=28^{\circ}C

Hence, the temperature  on a spring day 28 degree C.

7 0
3 years ago
(a) Two identical open boxes originally contain the same volume of water. One is kept at 15°C and the other at 85°C for the same
Tresset [83]

Explanation:

because as you can see beaker 2 has higher temperature. As volume is directly propotional

to temperature. So the the water molecules has

more energy so that's why levels are different.

6 0
2 years ago
Other questions:
  • How can you separate a mixture of 10 grams of salt and 10 grams of sand?
    12·1 answer
  • Which explains earthquakes and volcanic eruptions?
    9·2 answers
  • The range of electromagnetic waves placed in a certain order is called the
    9·2 answers
  • Which of the following is a scalar quantity
    5·1 answer
  • The word electromagnetism in physics is used to describe one of the fundamental forces of nature this force is between somatic p
    15·1 answer
  • An outdoor Wi-Fi unit for a picnic area has a 110 mW output and a range of about 38 m. What output power (in mW) would reduce it
    12·1 answer
  • Describe the frequency and wavelength range of radio waves
    14·1 answer
  • Which of these is an example of Newton’s first law of motion?
    14·1 answer
  • Describe how you can determine:<br>a) Volume of an irregular body<br>b) Density of a liquid​
    7·2 answers
  • A firefighter is using a hose and the flow rate of the water leaving the hose is 0.032 m3/s. At the end of the hose, the nozzle
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!