I'll give you a BRAINLIEST if you help me with these questions and they have to be correct.

2. Stars normally convert hydrogen into helium through nuclear fusion. That requires incredibly hot temperatures and high pressu

jolli1 [7]

Answer:

About 4,000 K and 10⁻¹⁷ atm

Explanation:

The Big Bang theory states that the Big Bang which is the origin of the universe was about 13.75 billion years ago, and the temperature a few seconds later was 10³²K

The first element began forming at about 3 minutes after the Big Bang with a temperature of 10⁹ K, the nuclei of simple elements

The nuclei of hydrogen and helium began combine with electrons at a temperature of 3,000 K to 4,000 K to form the first neutral atoms. The pressure of the universe at that stage was 10⁻¹⁷ atmospheres

6 0

3 years ago

A 19.0-kg cart is moving with a velocity of 7.20 m/s down a level hallway. A constant force of -13.0 N acts on the cart and its

gulaghasi [49]

Answer:

a. -369.36J

b. -123.9J

c. 9.52m

Explanation:

From the expression for kinetic energy

K. E=1/2mv^2

Since the mass is constant, but the velocity changes. Hence the change in kinetic energy is

K.E=1/2*19(3.6²-7.2²)

K.E= -369.36J

b. to determine the workdone by the force,we determine the distance moved.

But the acceleration is from

F=ma ,

a=f/m

a=-13/19

0.68m/s²

the distance moved is

s=v²/2a

s=3.6²/2*0.68

s=9.52m

Hence the work done is

W=force * distance

W=-13*9.52

W=-123.9J

d. the distance moved is

s=v²/2a

s=3.6²/2*0.68

s=9.52m

4 0

3 years ago

Read 2 more answers

An engine has an energy input of 125 J, and 35 J of that energy is transformed into useful energy. What is the efficiency of the

xeze [42]

The efficiency of the engine at the given useful energy and input energy is 28%.

The given parameters:

Input energy of the engine, = 125 J
Useful energy of the engine, 35 J

The efficiency of the engine is defined as the ratio of the output energy (useful energy) to the input energy and it is calculated as follows;

$efficiency\ = \frac{0ut put \ energy}{1nput \ energy} \times \ 100\%\\\\efficiency\ = \frac{35}{125} \times 100\%\\\\efficiency\ = 28 \ \%$

Thus, the efficiency of the engine at the given useful energy and input energy is 28%.

Learn more about efficiency of engine here: brainly.com/question/6751595

7 0

2 years ago

A block of mass 0.84 kg is suspended by a string which is wrapped so that it is at a radius of 0.061 m from the center of a pull

lora16 [44]

Answer:

$E_l = 1.713 J$

Explanation:

Given data:

mass of block is $M_b = 0.84 kg$

radius of block = 0.061 m

moment of inertia is $6.20 \times 10^{-3} kg m^2$

D is distance covered by block = 0.65 m

speed of block is 1.705 m/s

From conservation of momentum we have

$M_b g D = \frac{1}{2} M_b v^2 + \frac{1}{2} I \omega^2 + E_{loss}$

$0.84 \times 9.81 \times 0.65 = \frac{1}{2}\times 0.84 \times 1.705^2 +\frac{1}{2} \times 6.2 \times 10^{-3} [\frac{1.705}{0.061}]^2 + E_l$

solving for energy loss

$E_l = 1.713 J$

3 0

3 years ago

Identical objects, Object X and Object Y, are tied together by a string and placed at rest on an incline, as shown in the figure

goblinko [34]

The slope of the velocity time graph of an object moving with constant acceleration is constant

It will take approximately 3 seconds for the center of mass of Object X to reach point J near the bottom of the incline

The reason why the above time value is correct is given as follows:

Known parameters:

Initial velocity of the objects, u = 0

The graph in the question is a straight line graph with data points

(0, 0), (0.5, 1.0), (1.0, 2), (3.0, 6), and (3.5, 7)

Given that the slope of the velocity-time graph is constant, we have that the acceleration is constant and is given as follows;

$a = \dfrac{\Delta v}{\Delta t } = \dfrac{v_2 - v_1}{t_2 - t_1}$

Therefore;

$a = \dfrac{6 - 2}{3.0 - 1.0} = 2$

The acceleration, a ≈ 2 m/s²

The distance from the center of mass of the Object X to the point J near the bottom = 9 m

The equation for distance travelled is given as follows;

$s = u\cdot t + \dfrac{1}{2} \cdot a \cdot t^2$

Which gives;

$9 = 0\times t + \dfrac{1}{2} \times 2 \times t^2 = t^2$

t = √9 = 3

The time it will take the center of mass of Object X to reach point J near the bottom of the incline is t = 3 seconds

Learn more about motion under constant acceleration here:

brainly.com/question/16391598

6 0

3 years ago