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3 years ago

Facts about light years

Physics

2 answers:

Westkost [7]3 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]3 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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A stunt driver wants to make his car jump over 8 cars parked side by side below a horizontal ramp.

Genrish500 [490]

<u>Answer:</u>

a) Minimum speed must he drive off the horizontal ramp = 39.78 m/s

b) Minimum speed must he drive off the horizontal ramp with 7° above the horizontal = 23.93 m/s

<u>Explanation:</u>

a) The height of ramp = 1.5 meter

Horizontal distance he must clear = 22 meter

The car is having horizontal motion and vertical motion. In case of vertical motion the acceleration on the car is acceleration due to gravity.

We have equation of motion, $s= ut+\frac{1}{2} at^2$ , s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

In case of vertical motion initial velocity = 0 m/s, acceleration = 9.8 $m/s^2$ , we need to calculate time when displacement = 1.5 meter.

$1.5=0*t+\frac{1}{2} *9.8*t^2\\ \\ t = 0.553 seconds$

So the car has to cover a distance of 22 meter in 2.119 seconds.

So minimum speed required = 22/0.553 = 39.78 m/s

Minimum speed must he drive off the horizontal ramp = 39.78 m/s

b) When the take of angle is 7⁰ the vertical speed of car is not zero = V sin 7 = 0.122 V

So the in case of vertical motion we have initial velocity = 0.122 V, S = -1.5 meter( below ramp), acceleration = -9.8 $m/s^2$

Substituting

$-1.5=0.122V*t-\frac{1}{2} *9.8*t^2\\ \\ 4.9t^2-0.122Vt-1.5=0$

In case of horizontal motion

Horizontal speed of car = V cos 7 = 0.993V

So it has to travel 22 meter in t seconds

0.993Vt = 22, Vt = 22.155 m

Substituting in the equation $4.9t^2-0.122Vt-1.5=0$

We will get $4.9t^2-0.122*22.155-1.5=0\\ \\ t = 0.926 seconds$

Speed required = 22.155/0.926 = 23.93 m/s

Minimum speed must he drive off the horizontal ramp with 7° above the horizontal = 23.93 m/s

7 0

4 years ago

How many protons are in the nucleus of an aluminum atom

zlopas [31]

The atomic number of Aluminum is 13. The atomic number represents the number of protons in an atom.

6 0

3 years ago

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A toy cart moves with a kinetic energy of 30 J. If its speed is doubled, what is its kinetic energy?

klio [65]

Explanation:

KE is directly proportional to the square of velocity / speed.

if speed is 2 times (doubled) the KE will be

${2}^{2}$

= 4 times the original KE

$4 \times (30)$

$= 120 \: j$

8 0

3 years ago

Consider two samples of gas. Sample A consists of n moles and is kept at temperature T in container of volume V. Gas B consists

MrRissso [65]

Answer: e. P/2

Explanation:

For ideal gases, we have the relation:

P*V = n*R*T

where:

n = number of mols

R = Gas constant

T = temperature

V = volume

P = pressure.

We know that for sample A, we have n moles, a temperature T and a volume V, then the pressure of this sample will be:

Pa = (n*R*T)/V.

For sample B, we have:

n/2 moles, temperature T/2 and a volume V/2, then the pressure will be:

Pb = (n/2)*R*(T/2)*(2/V) = (n*R*T/V)*(2/4)

and:

(n*R*T/V) = Pa

Then we can replace it and we get:

Pb = (n*R*T/V)*(2/4) = Pa*(2/4) = Pa*(1/2) = Pa/2.

Then the correct option is e.

6 0

3 years ago

Convert 1600.0m to km

Dominik [7]

The answer should be 1.6 kilometers.

3 0

3 years ago

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