All categories

3 years ago

Question 18

Physics

1 answer:

Sedaia [141]3 years ago

3 0

Answer:

5.5 kg

Explanation:

The gravitational potential energy of an object is given by

$U=mgh$

where

m is its mass

g is the acceleration of gravity

h is the height of the object above the ground

For the rock in the problem, we know:

h = 12 m is the height above the ground

U = 650 J

g = 9.8 m/s^2

Therefore, we can solve the equation for m, the mass of the rock:

$m=\frac{U}{gh}=\frac{650}{(9.8)(12)}=5.5 kg$

You might be interested in

Two spectators at a soccer game in Montjuic Stadium see, and a moment later hear, the ball being kicked on the playing field. Th

Akimi4 [234]

Answer:

a) The distance of spectator A to the player is 79.2 m

b) The distance of spectator B to the player is 43.9 m

c) The distance between the two spectators is 90.6 m

Explanation:

a) Knowing the time it takes the sound to reach both spectators, we can calculate their position relative to the player, using this equation:

x = v * t

where:

x = position of the spectators

v = speed of sound

t = time

Then, the position for spectator A relative to the player is:

x = 343 m/s * 0.231 s = 79.2 m

b)For spectator B:

x = 343 m/s * 0.128 s

x = 43.9 m

The distance of spectator A and B to the player is 79.2 m and 43.9 m respectively.

c) To calculate the distance between the spectators, please see the attached figure. Notice that the distance between the spectators is the hypotenuse of the triangle formed by the sightline of both. We already know the longitude of the two sides. Then, using Pythagoras theorem:

(Distance AB)² = A² + B²

(Distance AB)² = (79.2 m)² + (43.9 m)²

Distance AB = 90. 6 m

6 0

3 years ago

You place a book on top of a spring and push down, compressing the spring by 10 cm. When you let go of the book, it is pushed up

enot [183]

At First, there is chemical Energy( in your muscels) which is Used to Push down the spring. This Energy becomes the Energy of the spring, which increases until you stop pushing. If you Put your hand away, the Energy of the spring will become kinetic energ. This Energy is at the highest Level the Moment the book ist Leaving the spring. Afterwards, the kinetic Energy decreases while the Gravitational Potential Energy increases.

4 0

3 years ago

Read 2 more answers

An iron wire has a cross-sectional area equal to 5.00×10⁻⁶ m² . Carry out the following steps to determine the drift speed of th

Doss [256]

In mass, there are 55.85 × 10⁻³ kg/mol in in 1 mole of iron.
The molar density of iron is equal to 1.41 × 10⁵ mol/m³.
The density of iron atoms is equal to 8.49 × 10²⁸ atoms/m³.
The number density of conduction electrons is equal to 1.70 × 10²⁹ conduction electrons/m³.
The drift speed of conduction electrons is equal to 2.21 × 10⁻⁴ m/s.

<h3>How to calculate the drift speed of the conduction electrons?</h3>

Mathematically, the drift speed of the conduction electrons can be calculated by using this formula:

V = (m × σ × V)/ρ × e × f × l)

V = I/(n × A × Q)

Where:

U represents the drift speed of the conduction electrons, in m/s.

m represents the molecular mass of the metal, in kg.

e represents the elementary charge, in C.

f represents the number of free electrons per atom.

σ represents the electric conductivity of the medium at a particular temperature in S/m.

ρ represents the density of the conductor, in kg/m³.

ℓ represents the length of the conductor, in m.

ΔV represents the voltage applied or potential difference across the conductor in V.

<h3>How many kilograms are there in 1 mole of iron? </h3>

Molar mass of iron = 55.85 g/mol.

In Kilograms, we have:

Mass = 55.85 × 1/1000

Mass = 55.85 × 10⁻³ kg/mol.

For the molar density of iron, we have:

Molar density = density/molar mass

Molar density = 7874/0.056

Molar density = 1.41 × 10⁵ mol/m³.

For the density of iron atoms, we have:

Density of iron atoms = Avogadro's constant × molar density

Density of iron atoms = 6.023 × 10²³ × 1.406 × 10⁵

Density of iron atoms = 8.49 × 10²⁸ atoms/m³.

For the number density of conduction electrons, we have:

Fe ---> Fe²⁺ + 2e⁻

Number density of conduction electrons = 2 conduction electrons/1 atom of iron

Number density of conduction electrons = 2 × 8.49 × 10²⁸

Number density of conduction electrons = 1.70 × 10²⁹ conduction electrons/m³.

For the drift speed of conduction electrons, we have:

V = I/(n × A × Q)

V = 30/(1.70 × 10²⁹ × 1.602 × 10⁻¹⁹ × 5 × 10⁻⁶)

Drift speed, V = 2.21 × 10⁻⁴ m/s.

Read more on drift speed here: brainly.com/question/15219891

#SPJ4

Complete Question:

An iron wire has a cross-sectional area of 5.00 x 10-6 m2. Carry out steps (a) through (e) to compute the drift speed of the conduction electrons in the wire.

(a) How many kilograms are there in 1 mole of iron?

(b) Starting with the density of iron and the result of part (a), compute the molar density of iron (the number of moles of iron per cubic meter).

(d) Obtain the number density of conduction electrons given that there are two conduction electrons per iron atom.

(e) If the wire carries a current of 30.0 A, calculate the drift speed of conduction electrons.

4 0

2 years ago

A race car is accelerating at 5m/s and then speeds up to a final velocity of 12 m/s if the race car driver finished this let of

noname [10]

Answer:

the acceleration of the car is 1.167 m/s²

Explanation:

Given;

initial velocity of the race car, u = 5 m/s

final velocity of the race car, v = 12 m/s

time to finish the race, t = 6 s

The acceleration of the car is calculated as;

a = (v - u) / t

a = (12 - 5) / (6)

a = 1.167 m/s²

Therefore, the acceleration of the car is 1.167 m/s²

3 0

3 years ago

Read 2 more answers

A periodic wave has a wavelength of 0.60 m and a speed of 40 m/s. What is the<br> wave frequency?

levacccp [35]

The correct answer is .05

4 0

3 years ago