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2 years ago

The speed of the wave depends on what?

1 answer:

4 0

The speed of a mechanical wave depends on the mechanical properties
of the medium through which the wave is traveling.

The speed of an electromagnetic wave depends on the electrical properties
of the medium through which the wave is traveling.

It's pretty well unanimous for choice A .

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Two marbles, one twice as heavy as the other, are dropped to the ground from the roof of a building. Just before hitting the gro

Andreyy89

Answer:

B. twice as much kinetic energy

Explanation:

Lets take the mass of the first marble =2 m

the mass of the second marble = m

We know that velocity of particle does not depends on their mass that is the velocity of both mass will be same after dropping from the roof.

We know that kinetic energy of a mass is given as

$KE=\dfrac{1}{2}Mv^2$

Kinetic energy for heavier mass

$KE=\dfrac{1}{2}\times 2m\times V^2$

Kinetic energy for light mass

$KE'=\dfrac{1}{2}\times m\times V^2$

KE=2 KE '

Form above two equation we can say that ,the kinetic energy for the heavier mass is twice the lighter mass.

Therefore the answer will be B.

7 0

3 years ago

Which best describes internet wikis as a source of scientific information

scoundrel [369]

Answer:

They are written or edited by anyone

Explanation:

5 0

2 years ago

A convex lens bulges outward in its center. and it refracts light rays towards its center. Which represents a convex lens? A) A

Mila [183]

Answer:

Its A

Explanation:

The lens bulges outward in its center, like reading glasses.

4 0

3 years ago

Read 2 more answers

Energy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is one kilocalorie, defined as 1 kc

Sergeeva-Olga [200]

Answer:

a) The student must run flight of stairs to lose 1.00 kg of fat 709.5 times.

b) Average power

P(w)= 1062.07 [w]

P(hp)=1.42 [hp]

c) This activity is highly unpractical, because the high amount of repetitions he has to due in order to lose, just 1 Kg of fat.

Explanation:

First, lets consider the required amount of work to move the mass of the student. (considering running stairs just as a vertical movement)

Work:

$W= F*d= m*g*d$

Where m is the mass of the student, g is gravity (9.8 m/s) and d is the total distance going up the stairs (0.15m *85steps= 12.75m )

$W= F*d= m*g*d=85* 9.8*12.75=10620.75 [J]$

Converting from Joules to Kcals:

$\frac{10620.75}{4186} =2.537 Kcal$

Now lets take into account the efficiency of the human body (20%)

2.537 ---> 20%

x ---> 100%

$x=\frac{2.537*100}{20} =12.685$

So the student is consuming 12.685 KCals each time he runs up the stairs.

Now,

1 g --> 9 Kcals

1000 g --> 9000KCals

Burning 1 g of fat, requieres 9 KCals, 1000g burns 9000KCals. So in order to burn a 1Kg of fat:

$\frac{9000Kcals}{12.685Kcals} =709.5 times$

He must run up the stairs 709.5 times, to burn 1 Kg of fat.

********************

For b) just converting units, taking into account the time lapse. (53103.75 is the 100% of the energy in joules, from converting 12.685Kcals to joules)

$Power=\frac{Joules}{Seconds} =\frac{53103.75}{50} =1062.075 [W]\\$

$P(hp)=\frac{P(w)}{745.7} =\frac{1062.075}{745.7} =1.42[hp]$

*****

4 0

3 years ago

How does frequency and pitch affect sound

aleksandr82 [10.1K]

The word that musicians use for frequency is pitch. The shorter the wavelength, the higher the frequency, and the higher the pitch, of the sound. In other words, short waves sound high; long waves sound low.

7 0

3 years ago