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2 years ago

Facts about light years

Physics

2 answers:

Westkost [7]2 years ago

5 0

I learn this in school a light years is how fast light can tralw in space i do not know how to spell that word

Anton [14]2 years ago

4 0

A light-year is how astronomers measure distance in space.
-Light can travel 300,000 kilometres in one seconds!
Light year is the distance that light travel can travel in one year.
-Light can also travel 9,00,000,000,000 kilometers.
-One light is about 10 trillion km.
-Almost 300 years ago ,a Danish scientist named olaus roemer,was the fist man to estimate the distance light travels in a year -and using that he figure out the approximate speed of light!

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When rocks experience high temperatures and differential stresses deep in the earth, their grains tend to ________?

pochemuha

Break into small particles. The heat causes the rock to break up and form pebbles or sand. Hope that helped. Have a nice day

4 0

3 years ago

Which example has the least kinetic energy

Stells [14]

Answer:

Explanation:

Let’s calculate the kinetic energy for all of the choices.

a. (1/2)(100)(100)^2 = 50(10000)=500,000

b. (1/2)(100)(1)^2 = 50

c. (1/2)(10)(100)^2 = 5(10000) = 50,000

d. (1/2)(1)(1)^2 = 0.5

We can see that (d) has the least kinetic energy.

5 0

2 years ago

1. Determine the image distance in each of the following.

miskamm [114]

It is given that for the convex lens,

Case 1.

u=−40cm

f=+15cm

Using lens formula

−

v=+24.3cm

The image in formed in this case at a distance of 24.3cm in left of lens.

Case 2.

A point source is placed in between the lens and the mirror at a distance of 40 cm from the lens i.e. the source is placed at the focus of mirror, then the rays after reflection becomes parallel for the lens such that

u=∞

f=15cm

Now, using mirror’s formula

∞

v=+15cm

The image is formed at a distance of 15cm in left of mirror

6 0

3 years ago

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

Why is it difficult to convert miles to yards

shepuryov [24]

There's really no "why", because it's not difficult at all.

Simply multiply the number of miles by 1,760, and bada boom,
there you have the same distance described in yards.

6 0

3 years ago

Read 2 more answers