18. The orbits of planets being elliptical was one the planetary laws developed by

The current in a wire varies with time according to the relationship 1=55A−(0.65A/s2)t2. (a) How many coulombs of charge pass a

mario62 [17]

Answer:

(A) Q = 321.1C (B) I = 42.8A

Explanation:

(a)Given I = 55A−(0.65A/s2)t²

I = dQ/dt

dQ = I×dt

To get an expression for Q we integrate with respect to t.

So Q = ∫I×dt =∫[55−(0.65)t²]dt

Q = [55t – 0.65/3×t³]

Q between t=0 and t= 7.5s

Q = [55×(7.5 – 0) – 0.65/3(7.5³– 0³)]

Q = 321.1C

(b) For a constant current I in the same time interval

I = Q/t = 321.1/7.5 = 42.8A.

3 0

2 years ago

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Why does your hand feel cool if you spill some alcohol on it?

son4ous [18]

<span>It takes heat to make something evaporate, so it takes heat from your arm. Alcohol easily evaporates at room temperature, so it feels cool. This is also why you feel cool when getting out of the pool. The water on your skin evaporates.

</span>

6 0

3 years ago

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An elephant pushes with 200 N on a load of trees. it then pushes these trees for 10 N. How much work did the elephant do?

Andreas93 [3]

Answer:

the answer is 2000Nm

Explanation:

wprk done = force × distance moved

w.d = 200N × 10m

w.d = 2000Nm

mark me as brainliest plyyzzz

7 0

3 years ago

Earth orbits the sun at an average circular radius of about 149.60 million kilometers every 365.26 Earth days.

kobusy [5.1K]

The Earth’s average orbital speed expressed in kilometers per hours is 107225.5 Km/hr and the mass of the sun is 2.58 x $10^{24}$ Kg

<h3>Relationship between Linear and angular speed</h3>

Linear speed is the product of angular speed and the maximum displacement of the particle. That is,

V = Wr

Where

V = Linear speed

W = Angular speed

r = Radius

Given that the earth orbits the sun at an average circular radius of about 149.60 million kilometers every 365.26 Earth days.

a) To determine the Earth’s average orbital speed, we will make use of the below formula to calculate angular speed

W = 2 $\pi$ /T

W = (2 x 3.143) / (365.26 x 24)

W = 6.283 / 876624

W = 7.2 x $10^{-4}$ Rad/hr

The Earth’s average orbital speed V = Wr

V = 7.2 x $10^{-4}$ x 149.6 x $10^{6}$

V = 107225.5 kilometers per hours.

b) Based on the information given in this question, to calculate the approximate mass of the Sun, we will use Kepler's 3rd law

M = (4 $\pi ^{2}$ $r^{3}$ ) / G $T^{2}$

M = (4 x 9.8696 x 3.35 x $10^{24}$ ) / (6.67 x $10^{-11}$ x 7.68 x $10^{11}$ <em>)</em>

<em>M = 1.32 x </em> $10^{26}$ / 51.226

M = 2.58 x $10^{24}$ Kg

Therefore, the Earth’s average orbital speed expressed in kilometers per hours is 107225.5 Km/hr and the mass of the sun is 2.58 x $10^{24}$ Kg

Learn more about Orbital Speed here: brainly.com/question/22247460

#SPJ1

3 0

1 year ago

You are given two objects of identical size, one made of aluminum and the other of lead. You hang each object separately from a

ollegr [7]

Answer:

Explanation:

Volume of lead object = volume of aluminium object = V

mass of lead object > mass of aluminium object

When both the objects immersed in water, the buoyant force acting on both the objects.

Buoyant force = Volume immersed x density of water x gravity

As the volume of both the objects is same, so the buoyant force acting on both the objects is same.

So, weight in air of lead object is more than the weight in air of aluminium object.

7 0

2 years ago