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2 years ago

Define light year and explain how and why light years are used to measure distances in the universe

1 answer:

5 0

Distances ANYWHERE could be described in terms of inches, feet,
yards, miles, kilometers, nanometers, centimeters, millimeters, or
even AU (Astronomical Units). But if you tried to use any of these
to describe the distance of anything away from the Earth's surface,
you'd be faced with a ridiculous number. It would be very hard to
remember this number or tell other people about it, and impractical
to write this number down in your notebook.

For example: The average distance between Earth and the moon is

38,440,145,820 centimeters,

and the distance to the nearest star outside the solar system
is approximately

1,671,433,491,000 kilometers.

Isn't that ridiculous ! ?

Obviously, we need much bigger units to describe these distances,
so that we can talk about them in more convenient numbers. so the
light year was invented to fill this need. It's simply the distance that
light travels through vacuum in one year.

Definition of 1 light year = exactly 9,460,730,472,580,<span>800 meters
</span>

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An artillery shell is launched on a flat, horizontal field at an angle of α = 40.8° with respect to the horizontal and with an i

Lina20 [59]

Answer:

1317.4 m

Explanation:

We are given that

Angle= $\alpha=40.8^{\circ}$

Initial speed = $v_0=346m/s$

We have to find the horizontal distance covered by the shell after 5.03 s.

Horizontal component of initial speed= $v_{ox}=v_0cos\theta=346cos40.8=261.9m/s$

Vertical component of initial speed= $v_{oy}=346sin40.8=226.1m/s$

Time=t=5.03 s

Horizontal distance = $Horizontal\;velocity\times time$

Using the formula

Horizontal distance= $261.9\times 5.03$

Horizontal distance=1317.4 m

Hence, the horizontal distance covered by the shell=1317.4 m

8 0

2 years ago

Haley is driving down a straight highway at 73 mph. A construction sign warns that the speed limit will drop to 55 mph in 0.50 m

gulaghasi [49]

Picture is my answer

3 0

3 years ago

Read 2 more answers

A person throws a ball with a force of 140 N that accelerates at 15 m/s? What is the mass of the

mr_godi [17]

Newton's 2nd law

$\tt \sum F=m.a$

input the value:

$\tt m=\dfrac{\Sum F}{a}=\dfrac{140~N}{15~m/s^2}=9.3~kg$

6 0

2 years ago

A truck is hauling a 300-kg log out of a ditch using a winch attached to the back of the truck. Knowing the winch applies a cons

torisob [31]

Answer:

0.1 s

Explanation:

The net force on the log is F - f = ma where F = force due to winch = 2850 N, f = kinetic frictional force = μmg where μ = coefficient of kinetic friction between log and ground = 0.45, m = mass of log = 300 kg and g = acceleration due to gravity = 9.8 m/s² and a = acceleration of log

So F - f = ma

F - μmg = ma

F/m - μg = a

So, substituting the values of the variables into the equation, we have

a = F/m - μg

a = 2850 N/300 kg - 0.45 × 9.8 m/s²

a = 9.5 m/s² - 4.41 m/s²

a = 5.09 m/s²

Since acceleration, a = (v - u)/t where u = initial velocity of log = 0 m/s (since it was a rest before being pulled out of the ditch), v = final velocity of log = 0.5 m/s and t = time taken for the log to reach a speed of 0.5 m/s.

So, making t subject of the formula, we have

t = (v - u)/a

substituting the values of the variables into the equation, we have

t = (v - u)/a

t = (0.5 m/s - 0 m/s)/5.09 m/s²

t = 0.5 m/s ÷ 5.09 m/s²

t = 0.098 s

t ≅ 0.1 s

6 0

2 years ago

Identify how the energy flows up through the ecosystem. Describe how decomposers help to cycle matter in an ecosystem and their

NNADVOKAT [17]

Answer:

Decomposers are organisms that break down dead or decaying organisms, they carry out decomposition, a process possible by only certain kingdoms, such as fungi. Like herbivores and predators, decomposers are heterotrophic, meaning that they use organic substrates to get their energy, carbon and nutrients for growth and development. While the terms decomposer and detritivore are often interchangeably used, detritivores ingest and digest dead matter internally, while decomposers directly absorb nutrients through external chemical and biological processes. Thus, invertebrates such as earthworms, woodlice, and sea cucumbers are technically detritivores, not decomposers, since they must ingest nutrients - they are unable to absorb them externally.

Explanation:

6 0

2 years ago