1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
guapka [62]
3 years ago
8

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

Physics
1 answer:
yan [13]3 years ago
3 0
Light years are the distance light can travel in a full year. They are used because there are really big distances in the universe that are easier to measure with a really large form of measurement (light years).
You might be interested in
A prismatic bar AB of length L and solid circular cross section (diameter d) is loaded by a distributed torque of constant inten
Lyrx [107]

Answer:

a) the maximum shear stress τ_{max} the bar is 16T_{max} /πd³

b) the angle of twist between the ends of the bar is 16tL² / πGd⁴  

Explanation:

Given the data in the question, as illustrated in the image below;

d is the diameter of the prismatic bar of length AB

t is the intensity of distributed torque

(a) Determine the maximum shear stress tmax in the bar

Maximum Applied torque  T_max = tL

we know that;

shear stress τ = 16T/πd³

where d is the diameter

so

τ_{max} = 16T_{max} /πd³

Therefore, the maximum shear stress τ_{max} the bar is 16T_{max} /πd³

(b) Determine the angle of twist between the ends of the bar.

let theta (\theta) be the angle of twist

polar moment of inertia I_p} = πd⁴/32

now from the second image;

lets length dx which is at distance of "x" from "B"

Torque distance x

T(x) = tx

Elemental angle twist = d\theta = T(x)dx / GI_{p}

so

d\theta = tx.dx / G(πd⁴/32)

d\theta = 32tx.dx / πGd⁴

so total angle of twist \theta will be;

\theta =  \int\limits^L_0  \, d\theta

\theta =  \int\limits^L_0  \, 32tx.dx / πGd⁴

\theta = 32t / πGd⁴  \int\limits^L_0  \, xdx

\theta = 32t / πGd⁴ [ L²/2]

\theta = 16tL² / πGd⁴  

Therefore,  the angle of twist between the ends of the bar is 16tL² / πGd⁴  

7 0
3 years ago
A racquetball strikes a wall with a speed of 30 m/s and rebounds in the opposite direction with a speed of 26 m/s. The collision
Fudgin [204]

Answer:

The average acceleration of the ball during the collision with the wall is a=2,800m/s^{2}

Explanation:

<u>Known Data</u>

We will asume initial speed has a negative direction, v_{i}=-30m/s, final speed has a positive direction, v_{f}=26m/s, \Delta t=20ms=0.020s and mass m_{b}.

<u>Initial momentum</u>

p_{i}=mv_{i}=(-30m/s)(m_{b})=-30m_{b}\ m/s

<u>final momentum</u>

p_{f}=mv_{f}=(26m/s)(m_{b})=26m_{b}\ m/s

<u>Impulse</u>

I=\Delta p=p_{f}-p_{i}=26m_{b}\ m/s-(-30m_{b}\ m/s)=56m_{b}\ m/s

<u>Average Force</u>

F=\frac{\Delta p}{\Delta t} =\frac{56m_{b}\ m/s}{0.020s} =2800m_{b} \ m/s^{2}

<u>Average acceleration</u>

F=ma, so a=\frac{F}{m_{b}}.

Therefore, a=\frac{2800m_{b} \ m/s^{2}}{m_{b}} =2800m/s^{2}

8 0
3 years ago
Are the two expressions equvalent 7(8x+5) and 48x + 35
Evgesh-ka [11]
Yes they are equivalent because 7x5=35 and 8x x 5=48x
4 0
3 years ago
Surface currents and waves are powered by what
Allisa [31]
It is powered by the Earth's rotation and the moon gives a little boost.
4 0
3 years ago
Determine the maximum r-value of the polar equation r =3+3 cos 0
AURORKA [14]

[r] =6  

Solve for r by simplifying both sides of the equation, then isolating the variable.

<em> </em>I hope this makes sense


8 0
3 years ago
Read 2 more answers
Other questions:
  • Electrons are important to electric current because they are able to__________.
    11·2 answers
  • Which is an example of a wedge?<br> a. bowl<br> b. spoon<br> c. fork<br> d. knife
    14·1 answer
  • How many protons and neutrons are present in an atom of 3919k? express your answer as integers separated by a comma?
    7·1 answer
  • A child bounces a 51 g superball on the sidewalk. The velocity change of the super bowl is from 22 m/s downward to 14 m/s upward
    7·1 answer
  • Lifting a box off the floor is an example of what type of force?
    5·2 answers
  • Light passing through the center of a lens will carry on undeviated.
    15·1 answer
  • When Danny Diver who weighs 500 N steps off a diving board 10 m above the water, he hits the water with kinetic energy of
    11·1 answer
  • A car traveling at 5m/s starts to speed up after 3 seconds its velocity has increased to 11 m/s what is its acceleration
    10·1 answer
  • It is necessary to to secure an inflated balloon tightly give reason
    6·1 answer
  • Every summer I drive to Pennsylvania. It is 895 km to get there. If I average 100 km/hr, how much time will I spend driving?
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!