All categories

3 years ago

Explain why materials such as plastic foam, feathers, and fur are poor conductors of heat.

1 answer:

7 0

The atoms of some materials have no free electrons in their outer orbits. These electrons are busy doing other jobs, like being shared in the orbits of two adjacent atoms. They are so closely held that it is very difficult to pull them away. Most compounds of carbon and hydrogen are like this.

Plastics, whose molecules are made from long combinations of carbon and hydrogen atoms, have few or no free electrons. This means that plastics are poor conductors of electricity (and they are also poor conductors of heat). hope that helped.

You might be interested in

What is the Ozone layer?

yaroslaw [1]

"a layer in the earth's stratosphere at an altitude of about 6.2 miles (10 km) containing a high concentration of ozone, which absorbs most of the ultraviolet radiation reaching the earth from the sun."

Hope this helps!

4 0

3 years ago

Read 2 more answers

A student visits the beach and wants to explore how landforms, such as sand dunes, are the result of changes caused by wind. wha

posledela

C Camera. I think this because you can make timelapses with cameras which makes it easy to see.

3 0

3 years ago

Read 2 more answers

3. An athlete makes a long jump and follows a projectile motion. Air resistance is negligible. Which one of the following statem

yulyashka [42]

Answer:

Option (b) is correct.

Explanation:

The motion under the influence of gravity is called projectile motion.

The acceleration due to gravity is constant through out the motion and it is always acting downwards.

When an athlete jumps and follow the projectile path, it always have the same horizontal velocity as there is no acceleration in the horizontal direction.

Also he has the vertical acceleration constant which is equal to the acceleration due to gravity and acts towards the center of earth.

Option (b) is correct.

6 0

3 years ago

Can anyone tell me what's the base quantities for Force, Pressure and Charge?

mr Goodwill [35]

Force, pressure, and charge are all what are called derived units. They come from algebraic combinations of base units, measures of things like length, time, temperature, mass, and current. Speed, for instance, is a derived unit, since it's a combination of length and time in the form [speed] = [length] / [time] (miles per hour, meters per second, etc.)

Force is defined with Newton's equation F = ma, where m is an object's mass and a is its acceleration. It's unit is kg·m/s², which scientists have called a Newton. (Example: They used 9 Newtons of force)

Pressure is force applied over an area, defined by the equation P = F/A. We can derive its from Newtons to get a unit of N/m², a unit scientists call the Pascal. (Example: Applying 100 Pascals of pressure)

Finally, charge is given by the equation Q = It, where I is the current flowing through an object and t is how long that current flows through. It has a unit of A·s (ampere-seconds), but scientist call this unit a Coulomb. (Example: 20 Coulombs of charge)

4 0

3 years ago

During their physics field trip to the amusement park, Leslie and Maria took a ride on the Whirligig. The Whirligig ride consist

grandymaker [24]

Answer:

a) frequency = 0.1724 Hz

b) Period = 5.8 sec

c) speed = 7.04 m/s

d) acceleration = 7.62 m/s²

Explanation:

Given that;

radius = 6.5m

time period = 5.8 sec every circle

a) the frequency

frequency is the number of rotation in unit time

frequency = 1 / time period = 1/5.8

frequency = 0.1724 Hz

b) the period

period is time taken in one rotation

period = total time / rotation = 5.8 / 1

Period = 5.8 sec

c) the speed

speed = distance/time = circumference/time period = 2πr / t = (2π×6.5) / 5.8

speed = 7.04 m/s

d) acceleration

To find the acceleration we take the linear velocity squared divided by the radius of the circle.

acceleration = v² / r = (7.04)² / 6.5 = 49.5616 / 6.5

acceleration = 7.62 m/s²

6 0

3 years ago