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
Irina-Kira [14]
3 years ago
13

The distance from Earth to the North Star is about 430 light-years. Which of the following statements describes why scientists u

se the light-year unit to measure distance in space?
A.) A light-year is very small and distance in space are very small

B.) A light-year unit is very small and the distance in space are very large

C.) A light-year unit is very large and distance in space are very small

D.) A light-year unit is very large and distance in space are very large
Physics
1 answer:
vampirchik [111]3 years ago
7 0

Answer:

D

Explanation:

D

You might be interested in
Which of the following is the same in all frames of reference?
Ksju [112]
The correct option is B.
The length of an object, the mass of an object and the rate of time passage for an object can change depending on the situation which the object is subject to. For instance in space, the mass and the velocity of an object usually change. But, the value of the speed of light in the space is the same for all observers regardless of the motion of an object, that is, the speed of light is a constant.<span />
4 0
4 years ago
An electric furnace is to melt 40 kg of aluminium/hour. The initial temperature of aluminium is 32°C. Given that aluminium has s
gizmo_the_mogwai [7]

Answer:

Part a)

P = 13.93 kW

Part b)

R = 8357.6 Cents

Explanation:

Part A)

heat required to melt the aluminium is given by

Q = ms\Delta T + mL

here we have

Q = 40(950)(680 - 32) + 40(450 \times 10^3)

Q = 24624 kJ + 18000 kJ

Q = 42624 kJ

Since this is the amount of aluminium per hour

so power required to melt is given by

P = \frac{Q}{t}

P = \frac{42624}{3600} kW

P = 11.84 kW

Since the efficiency is 85% so actual power required will be

P = \frac{11.84}{0.85} = 13.93 kW

Part B)

Total energy consumed by the furnace for 30 hours

Energy = power \times time

Energy = 13.93 kW\times 30 h

Energy = 417.9 kWh

now the total cost of energy consumption is given as

R = P \times 20 \frac{Cents}{kWh}

R = 417.9 kWh\times  20 \frac{cents}{kWh}

R = 8357.6 Cents

3 0
3 years ago
A hopper jumps straight up to a height of 1.3 m. With what velocity did he leave the floor
xxMikexx [17]

The velocity with which the jumper leaves the floor is 5.1 m/s.

<h3>What is the initial velocity of the jumper?</h3>

The initial velocity of the jumper or the velocity with which the jumper leaves the floor is calculated by applying the principle of conservation of energy as shown below.

Kinetic energy of the jumper at the floor = Potential energy of the jumper at the maximum height

¹/₂mv² = mgh

v² = 2gh

v = √2gh

where;

  • v is the initial velocity of the jumper on the floor
  • h is the maximum height reached by the jumper
  • g is acceleration due to gravity

v = √(2 x 9.8 x 1.3)

v = 5.1 m/s

Learn more about initial velocity here: brainly.com/question/19365526
#SPJ1

3 0
1 year ago
6th grade science !!!!!!!!!!!!!!!​
posledela

Answer:

71

Explanation:

5 0
3 years ago
Which of the following statements below is correct?
Mamont248 [21]
C. is correct. when you make a pizza, you see the the meat or pepperoni or cheese heating up and sometimes melted. (thats physical). on the inside the crust in heated and the toppings are cooked (chemical)
5 0
3 years ago
Other questions:
  • The motion of a free falling body is an example of __________ motion​
    14·2 answers
  • A plane mirror and a concave mirror (f = 8.20 cm) are facing each other and are separated by a distance of 25.0 cm. An object is
    11·2 answers
  • If the force of gravity suddenly stopped acting on the planets, they would
    15·2 answers
  • An object goes from 10 m/s to 2 m/s in 2 seconds, what's its acceleration?
    12·1 answer
  • The kinetic energy of a rotating body is generally written as K=12Iω2, where I is the moment of inertia. Find the moment of iner
    15·1 answer
  • What is one common product use microwaves<br><br><br><br> dont have much timeee
    10·1 answer
  • Answer in detail? Describe an activity that gives an understanding of ‘Electrostatic force’.
    5·1 answer
  • A solar panel is used to collect energy from the sun and change it into other forms of energy. The picture below shows some sola
    13·1 answer
  • The acceleration due to gravity on the moon is about 5.4ft/s2. if your weight is 150lbf on earth
    10·1 answer
  • In music, the note G above middle C has a frequency of about 392 hertz. If the speed of sound in the air is 340 m/s, what is the
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!