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nikitadnepr [17]

2 years ago

11

How many stars can be seen without a telescope on earth

1 answer:

belka [17]2 years ago

5 0

There are only about 5,000 stars visible to the naked, average, human eye, . And, because the Earth itself gets in the way, you can only see about a half of those from where you stand.

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Objects are lighter on the moon than they are on earth. if an object A weighs 25lbs on the Moon and another object B weighs 25 N

solong [7]

Answer:

a. Object A

Explanation:

The mass of an object implies the quantity of matter in it, while the weight is the amount of gravitational force applied on an object.

The object A has a mass of 25 lbs, but object B on the earth has a weight, W, of 25 N.

So that,

For object A on the moon, mass = 25 lbs

For object B on the earth, W = 25 N,

W = m x g

25 = m x 10 (g = 10 m/ $s^{2}$ )

m = $\frac{25}{10}$

= 2.5 lbs

Mass of object B is 2.5 lbs.

Therefore, the mass of the object A is more than that of B.

5 0

2 years ago

A Scooter travelling at 10m/s speed up to 20m/s in 4 sec.find the acceleration of scooter

stira [4]

Answer:

2.5 m/s²

Explanation:

Given,

Initial speed ( u ) = 10 m/s

Final speed ( v ) = 20 m/s

Time ( t ) = 4 seconds

To find : Acceleration ( a ) = ?

Formula : -

a = ( v - u ) / t

a = ( 20 - 10 ) / 4

= 10 / 4

= 5 / 2

a = 2.5 m/s²

Therefore,

The acceleration of the scooter is 2.5 m/s²

7 0

2 years ago

A research submarine has a 20-cm-diameter window that is 9.0 cm thick. The manufacturer says the window can withstand forces up

Ratling [72]

Answer:

The maximum safe depth in salt water is 3758.2 m.

Explanation:

Given that,

Diameter = 20 cm

Radius = 10 cm

Thickness = 9.0 cm

Force $F = 1.2\times10^{6}\ N$

Inside pressure = 1.0 atm

We need to calculate the area

Using formula of area

$A=\pi\times r^2$

Put the value into the formula

$A=\pi\times(10\times10^{-2})^2$

$A=0.0314\ m^2$

We need to calculate the pressure

Using formula of pressure

$P=\dfrac{F}{A}$

Put the value into the formula

$P=\dfrac{1.2\times10^{6}}{0.0314}$

$P=38216560.50\ Pa$

$P=3.8\times10^{7}\ Pa$

We need to calculate the maximum depth

Using equation of pressure

$P=P_{atm}+\rho gh$

$h=\dfrac{P-P_{atm}}{\rho g}$

Put the value into the formula

$h=\dfrac{3.8\times10^{7}-101325}{1029\times9.8}$

$h=3758.2\ m$

Hence, The maximum safe depth in salt water is 3758.2 m.

4 0

2 years ago

Which of the following is a TRUE

DENIUS [597]

The statement that is the most true regarding the states of matter is the first statement.

A. Most matter on Earth exists as a solid, liquid, or gas.

This is correct since most of the matter on Earth exists in those 3 states, meanwhile plasma is not a state that most of matter on earth is found in since it is mostly associated to stars and the external galactic regions.

Therefore, B is incorrect.

C is false, since almost of all of the matter on earth can transform and change through each of the 3 states of matter, solid, liquid, and gas.

D is false since most of the matter in universe is actually made out of plasma instead of a liquid. In fact, over 99% of the known universe's matter is said to consist of plasma.

7 0

3 years ago

A 2 L balloon filled with gas is warmed from 280 K to 700 K. What is the volume of the gas after it is heated?

irakobra [83]

Answer:

New volume, v2 = 0.8L

Explanation:

<u>Given the following data;</u>

Original Volume = 2L

Original Temperature = 280K

New Temperature = 700K

To find new volume V2, we would use Charles' law.

Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.

Mathematically, Charles is given by;

$VT = K$

$\frac{V1}{T1} = \frac{V2}{T2}$

$\frac{V1}{T1} = \frac{V2}{T2}$

Making V2 as the subject formula, we have;

$V_{2}= \frac{V1}{T1} * T_{2}$

$V_{2}= \frac{2}{700} * 280$

$V_{2}= 0.0029 * 280$

V2 = 0.8L

Therefore, the volume of the gas after it is heated is 0.8L.

7 0

2 years ago