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3 years ago

What is the approximate percentage change in the Earth-Sun distance between June 21 and December 21?

1 answer:

5 0

For the purpose of the exercise, we can assume that the Earth is at perihelion (closest point to the Sun) on December 21st (in reality, it happens around January 4th) and that the Earth is at aphelion (farthest point from the Sun) on June 21st (in reality, this happens around July 4th). The distance Earth-Sun is the following:
- Perihelion: 147.1 milion km
- Aphelion: 152.1 milion km
- Average distance: 149.6 milion km
So, we can calculate the percentage change with respect to the average distance as:
$d= \frac{d(aphelion)-d(perihelion)}{d(average)}\cdot 100= \frac{152.1-147.1}{149.6}\cdot 100=3.3 \%$

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A slice of bread contains about 100 kcal. If specific heat of a person were 1.00 kcal/kg·°C, by how many °C would the temperatur

almond37 [142]

Answer:

(c) 1.43°C

Explanation:

If the energy in the bread are converted to heat.

Then, The heat transferred from the bread to person = 100 kcal.

From specific heat capacity,

Q = cmΔT............................ equation 1

Where Q = quantity of heat, m = mass of the person, c = specific heat capacity of the person, Δ = increase in temperature.

Making ΔT the subject the equation 1,

ΔT = Q/cm........................ equation 2

Where Q = 100 kcal, c= 1.00 kcal/kg.°C, m = 70.0 kg

Substituting these values into equation 2,

ΔT = 100/(1×70)

ΔT = 100/70

ΔT = 1.428

ΔT ≈ 1.43°C

The increase in temperature of the body is = 1.43°C

The right option is (c) 1.43°C

5 0

3 years ago

True or false: Waves transfer matter as they travel.

Natalija [7]

Answer: false

Explanation: hope that helped

4 0

3 years ago

Read 2 more answers

The need for sustainable energy resources ??

gizmo_the_mogwai [7]

Answer:

Sustainable energy is essential to meet uncontrolled rising demand for energy, reduce pollution and shift to resources that can be used again and again.

Explanation:

Considering the Sustainable Goals floated by United Nation, it is essential for all countries to improve their score in all the SD goals.

One of the SD goal is to shift to sustainable energy.

Sustainable energy is essential from following three points

- Reuse of energy source again and again to outcome the fear of resource depletion

- Sustainable energy source shall ensure cleaner environment

- Sustainable energy sources are also essential to meet the rising consumption of energy with time all across the globe.

Some common examples are - Solar energy, Wind Energy, Energy from nuclear fuels etc.

6 0

3 years ago

Define a combination circuit.

Neporo4naja [7]

Answer:

a circuit that is a blend of series paths and parallel paths. See Figure for a visual explanation. Most circuits are of this variety. Don't be afraid to tackle these circuits as far as the math goes.

7 0

3 years ago

A merry-go-round is rotating at an angular speed of 0.2 radians/s. Its motor falls off and it rotates freely. A technician jumps

I am Lyosha [343]

Answer:

I₁ =1250 kg.m²

Explanation:

Given that

Angular speed of Merry ,ω₁= 0.2 rad/s

Angular speed of technician ,ω₂= 0.04 rad/s

Moment of the inertia of the technician ,I₂= 5000 kg.m²

Lets assume that

Moment of the inertia of merry with respected to the ground=I₁

There is no any external torque ,that is why angular momentum of the system will be conserve.

Now by conserving angular momentum

I₁ ω₁=(I₁+I₂)ω₂

I₁ x 0.2 = (I₁ +5000 ) x 0.04

I₁ (0.2-0.04) = 5000 x 0.04

$I_1=\dfrac{5000\times 0.04}{0.2-0.04}$

I₁ =1250 kg.m²

5 0

3 years ago