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3 years ago

A light-year is _______________

2 answers:

3 0

The correct answer would be A "<span>A light-year is the distance light travels in a year.

This is considered a unit of distance connected to the distance that light can travel in one year. It is proved that light travels at 300,000 km per second so, in 1 year, it might travel 10 trillion km.

</span>

ehidna [41]3 years ago

3 0

The answer is A, the distance light travels in a year.

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A crane raises a crate with a mass of 150 kg to a height of 20 m. Given that

Virty [35]

Answer:

$\boxed {\boxed {\sf 29,400 \ Joules}}$

Explanation:

Gravitational potential energy is the energy an object possesses due to its position. It is the product of mass, height, and acceleration due to gravity.

$E_P= m \times g \times h$

The object has a mass of 150 kilograms and is raised to a height of 20 meters. Since this is on Earth, the acceleration due to gravity is 9.8 meters per square second.

m= 150 kg
g= 9.8 m/s²
h= 20 m

Substitute the values into the formula.

$E_p= 150 \ kg \times 9.8 \ m/s^2 \times 20 \ m$

Multiply the three numbers and their units together.

$E_p=1470 \ kg*m/s^2 \times 20 m$

$E_p=29400 \ kg*m^2/s^2$

Convert the units.

1 kilogram meter square per second squared (1 kg *m²/s²) is equal to 1 Joule (J). Our answer of 29,400 kg*m²/s² is equal to 29,400 Joules.

$E_p= 29,400 \ J$

The crate has <u>29,400 Joules</u> of potential energy.

7 0

3 years ago

Each wheel of a 320 kg motorcycle is 52 cm in diameter and has rotational inertia 2.1 kg m2 . The cycle and its 75 kg rider are

Amiraneli [1.4K]

Answer:

The value is $h = 32.91 \ m$

Explanation:

From the question we are told that

The diameter of each wheel is $d = 52 \ cm = 0.52 \ m$

The mass of the motorcycle is $m = 320 \ kg$

The rotational kinetic inertia is $I = 2.1 \ kg \ m^2$

The mass of the rider is $m_r = 75 \ kg$

The velocity is $v = 85 \ km/hr = 23.61 \ m/s$

Generally the radius of the wheel is mathematically represented as

$r = \frac{d}{2}$

=> $r = \frac{0.52}{2}$

=> $r = 0.26 \ m$

Generally from the law of energy conservation

Potential energy attained by system(motorcycle and rider ) = Kinetic energy of the system + rotational kinetic energy of both wheels of the motorcycle

=> $Mgh = \frac{1}{2} Mv^2 + \frac{1}{2} Iw^2 + \frac{1}{2} Iw^2$

=> $Mgh = \frac{1}{2} * Mv^2 + Iw^2$

Here $w$ is the angular velocity which is mathematically represented as

$w = \frac{v }{r }$

$Mgh = \frac{1}{2} * Mv^2 + I \frac{v}{r} ^2$

Here $M = m_r + m$

$M = 320 + 75$

$M = 395 \ kg$

$395 * 9.8 * h = 0.5 * 395 * (23.61)^2 + 2.1 *[\frac{ 23.61}{ 0.26} ] ^2$

=> $h = 32.91 \ m$

7 0

4 years ago

Calculate the electrostatic force that a small sphere A, possessing a net charge of 2.0 x 10^-6 Coulombs exerts on another small

Anni [7]

Answer:

F = 5.33*10^-4N

Explanation:

to find the electrostatic force you use the Coulomb's law, given by the formula:

$F=k\frac{q_Aq_B}{r^2}$

k: Coulomb's constant = 8.89*10^9 Nm^2/C^2

q_a: charge of A = 2.0*10^{-6}C

q_B: charge of B = -3.0*10^{-6}C

r: distance between the spheres = 10.0m

By replacing all these values you obtain:

$F=(8.89*10^9Nm^2/C^2)\frac{(2.0*10^{-6}C)(-3.0*10^{-6}C)}{(10.0m)^2}=5.33*10^{-4}N$

hence, the forcebetween the spheres is about 5.33*10^-4N

3 0

3 years ago

Please help me with this one

katen-ka-za [31]

Both of the pictures show how one picture is I believe in fall and the other one is in the forest and maybe in spring or summer. Also, the two pictures show 2 different animals. And maybe hunting for 2 different foods for them to survive.

* Hopefully this helps:) Mark me the brainliest:)

5 0

3 years ago

Now put that book 5 feet in the air. What kind of energy does the book have? Explain.

erastova [34]

Answer:

Gravitational potential energy

Explanation:

The book is put 5 feet in the air, which means 5 feet above the ground. An object which is located to a certain height above the ground possesses a form of energy called gravitational potential energy, which is the energy due to the fact that the object has "potential" to transform this energy into other forms of energy (e.g. kinetic energy, if the book is released and it starts moving).

The value of the gravitational potential energy of the object is given by the formula:

$U=mgh$

where

m is the mass of the object

g is the gravitational acceleration (9.8 m/s^2)

h is the height of the book above the ground (in this case, 5 feet)

So, we see that the gravitational potential energy is proportional to both the mass and the height of the object.

8 0

4 years ago