Can someone let me know if I got these questions right please

Answer:

0.79g/cm³

Explanation:

Given parameters:

Volume of acetone = 120cm³

Mass of empty flask  = 49.74g

Mass of flask + acetone  = 144.78g

Unknown:

Density of acetone = ?

Solution:

Density is the mass per given volume of a substance. It is mathematically expressed as;

   Density  = [tex]\frac{mass}{volume}[/tex]  

     Mass of acetone  =( mass of flask + acetone)   - mass of empty flask

     Mass of acetone = 144.78  - 49.74  = 95.04g

Now insert the parameters and solve;

 Density  = [tex]\frac{95.04}{120}[/tex]   = 0.79g/cm³

Answer: i could prolly answer if it made more sense. which of the following where?

Answer:

D: the ball is not accelerating because it is slowing down

Explanation:

if the was no friction, then the ball would most likely pick up speed and never stop, like it would with it being on a hill covered in ice, it would pick up speed and never slow down (well, it would slow down, just at a point where it looks like it would never stop.

Answer:

Vf = 39.2 m/s

h = 78.4 m

Explanation:

Using first equation of motion for vertical motion:

Vf = Vi + gt

where,

Vf = Final Velocity = ?

Vi = Initial Velocity = 0 m/s

g = 9.8 m/s²

t = time taken = 4 s

Therefore,

Vf = 0 m/s + (9.8 m/s²)(4 s)

Vf = 39.2 m/s

Now, we use second equation of motion

h = Vi t + (1/2)gt²

where,

h = height covered = ?

Therefore,

h = (0 m/s)(4 s) + (1/2)(9.8 m/s²)(4 s)²

h = 78.4 m

Answer:

I = 6.42 A

Explanation:

Given that,

Potential difference, V = 0.9 V

Length of the wire, l = 1.5 m

Area of cross section, [tex]A=0.6\ mm^2=6\times 10^{-7}\ m^2[/tex]

We need to find the current in the wire. Let I is current. We can find it using Ohm's law as follows :

V = IR

Where R is the resistance of the wire

[tex]I=\dfrac{V}{R}\\\\I=\dfrac{V}{\rho \dfrac{l}{A}}\\\\I=\dfrac{0.9}{5.6\times 10^{-8}\times \dfrac{1.5}{6\times 10^{-7}}}\\\\I=6.42\ A[/tex]

So, the current in the wire is 6.42 A.

Answer:

[tex]1.694*10^3KW/hr[/tex]

Explanation:

Formula:

[tex]KW/hr=E_{(change)}[/tex]

[tex]P=\frac{E}{t}[/tex]

[tex](KW)(s)=1000J[/tex]

[tex](3600)(KW)(s)=3600*1000J[/tex]

[tex]KW=3.6*10^6[/tex]

[tex]\frac{6.1*10^9}{3.6*10^6}=\frac{x}{1KW}[/tex]

[tex]1.694*10^3KW/hr[/tex]

Hope it helps

Answer:

the answers is C. acceleration

Answer:the  Minimum speed , v of the roller coster = 17.0 m/s --c

Explanation:

According to Newton's First law  of Motion which state that all object will remain at rest unless an external force is applied on the body to act otherwise.

Therefore the   Force exerted/ acting  on the surface of  the roller coaster will be equal to 0,

Net Force = 0

Remember that , Force = mg = Mv ²/r = 0

 Net Force =mv ² / r - mg = 0

mv²/ r - mg = 0

(diving through by m)

v²/r -g = 0

v² = gr

v= [tex]\sqrt{gr}[/tex]

where g, acceleration due to gravity= 9.8m/s2 and radius, r = 29.5m

v=  [tex]\sqrt{9.8m/s2 X 29.5m }[/tex]

v =[tex]\sqrt{ 289}[/tex]

v=  17.0 m/s

Therefore, the  Minimum speed , v of the roller coaster = 17.0 m/s

Answer:

nucleus made of protons and neutrons because the chemical atom is determined my a number

Answer:

Explanation:

Given

torque,τ= 0.97N

radius r= 35cm to m= 0.35m

mass m= 0.75kg

Required

angular acceleration

First, we need the  moment of inertial of the wheel

I=mr^2

I=0.75*0.35^2

I=0.75*0.1225

I=0.09kgm^2

Secondly, the angular moment of inertial is expressed as

a=τ/I

a=0.97/0.09

a=10.77rads/s^2

a=11 rad/s^2 approx.

Answer:

B) The rod is subject to tensile stress

Explanation:

Tensile stress is the force induced in the body per unit area in response to externally applied force, which stretches the body.

Tensile stress is attached with tensile forces. It is makes material elongate along the axis of the applied load.

It is given as magnitude (F) of the force that is applied along an elastic rod divided by the cross sectional area (A) of the rod in a direction that is perpendicular to the applied force.

materials such as Doctile have the ability to withstand the load while brittle materials who not have the ability they fail before reaching the ultimate material strength.

Answer:D

Explanation:

just got it right

Answer:D

Explanation:

taking the test

Infared = used by police

gamma = short wavelength

radio = largest wavelength

visible = only ones we can see

Answer: police use infred waves,

radio waves have largest wave length, the

only part of the spectrum seen by humans is visible waves

gamma waves have shortest wave length

Explanation:

Answer:The answer will be B :) hope this helps!

Explanation:

Answer:

hellllllllooooooooooooooo

Answer:no

Explanation:

Answer:

Why do you do sports, when you could be a doctor and helping the sick children, or saving the worlds ocean?

Explanation:

Answer:

a = 2.77 [m/s²]

Explanation:

To solve this problem we must use the following equation of kinematics.

[tex]v_{f} =v_{o} -a*t[/tex]

where:

Vf = final velocity = 19 [m/s]

Vo = initial velocity = 44 [m/s]

a = acceleration [m/s²]

t = time = 9 [s]

Note: The negative sign in the above equation means that the train is decreasing its velocity.

19 = 44 - a*9

9*a = 44 -19

a = 2.77 [m/s²]

Answer:A

Explanation:

Answer:

D. Mixtures are classified based on the distribution of particles in them.

Explanation:

A is wrong because mixtures are not made of elements that are bonded together chemically.

B is wrong because elements and compounds are types of pure substances.

C is wrong because pure substances are not made up of mixtures.

Please give brainliest

Answer:

Vf = 86.34 [m/s]

Explanation:

To solve this problem we must use the following equation of kinematics.

[tex]v_{f} ^{2} =v_{o} ^{2} +2*g*y[/tex]

where:

Vf = final velocity [m/s]

Vo = initial velocity = 0 (falls from the rest)

g = gravity acceleration = 9.81 [m/s²]

y = distance = 380 [m]

Vf² = 0 + (2*9.81*380)

Vf = 86.34 [m/s]

Note: The pisitive sign in the equation above means that the movement goes in the same direction of the gravity acceleration, therefore the velocity is increasing when the penny falls.

Answer:

When the cold weather fills hard surfaces with water, it causes it to freeze and expand, causing cracks in the surface.

Answer:

Humus

Explanation:

Its Humus I believe. I remember learning something like this.

Explanation:

An object's weight depends on the pull of the gravitating object but the object's mass is independent of the gravity.

Answer:

The value is  [tex]F = 34.3 \ N[/tex]

Explanation:

From the question we are told that

    The mass of the shed is  [tex]m = 25 \ kg[/tex]

    The length of the rope is  [tex]l = 5.0 \ m[/tex]

    The angular speed of the shed is [tex]w = 5 rev/minute = \frac{2* \pi * 5}{60 }= 0.524 \ rad/sec[/tex]

Generally the force exerted on the shed is mathematically represented as

     [tex]F = m * w^2 * l[/tex]

=>  [tex]F = 25 * 0.524^2 * 5[/tex]

=>  [tex]F = 34.3 \ N[/tex]    

The magnitude of the centripetal force on the sled by the rope is 34.3 N.

The given parameters:

The angular speed of the sled is calculated as follows;

[tex]\omega = 5 \ \frac{rev}{\min} \times \frac{2\pi \ rad}{1 \ rev} \times \frac{1 \min}{60 \ s} \\\\\omega = 0.524 \ rad/s[/tex]

The magnitude of the centripetal force on the sled by the rope is calculated as follows;

[tex]F = ma_c\\\\F = m\omega ^2 r\\\\F = 25 \times (0.524)^2 \times 5\\\\F = 34.3 \ N[/tex]

Learn more here:https://brainly.com/question/20905151

Answer:

a = 0

Explanation:

The velocity of a sound wave in a straight line is 660 mph. The wave is moving with a constant velocity. It means that the change in velocity is equal to 0.

We know that acceleration of an object is equal to the change in velocity divided by time taken. But here the change in velocity is 0. As a result the acceleration of the sound wave is 0.

Answer:

Both daughter and parent atoms

Explanation:

Daughter atoms are an offshoot of daughter elements, and are formed when a radioactive element undergoes radioactive decay. The new element is the daughter element, while the initial, the former element is the parent element.

Same analogy goes for daughter atoms and parent atoms..

Radiometric dating is also called radioactive dating or even radioisotope dating. It is a technique that is used to date materials like carbon or even rocks, that has trace radioactive impurities selectively incorporated into it when they were formed.

Radiometric dating is defined as the technique, which is used to date rocks, carbon, or radioactive impurities. The rocks that consist of parent and daughter atoms are used for accurate radiometric dating.

The correct statement for the blank is:

Accurate radiometric dating typically requires that rock contains a measurable amount of parent and daughter atoms.

It can be defined as:

1. Daughter atoms are formed when the radioactive element undergoes radioactive decay. The element formed is the daughter element from which it is formed is known as the parent element.

2. A radioactive isotope is also called radioactive dating, which is used to date rocks and radioactive elements. These elements are incorporated into the elements when they are formed.

Thus, the correct answer is parent and daughter atoms.

To know more about radioactive dating, refer to the following link:

https://brainly.com/question/3444297

Answer: 1. B. The number of electrons emitted from the metal per second increases.

2. The maximum speed of the emitted electrons increases.

The stopping potential increases

Explanation:

Photoelectric effect is simply referred to as the emission of electrons that occurs when there's an electromagnetic radiation. An example of such electromagnetic radiation is when material is being hit by light.

Assuming that the light incident on the metal surface causes electrons to be ejected from the metal, the number of electrons emitted from the metal per second increases if the intensity of the incident light is increased.

Also, if the initial light incident on the metal surface causes electrons to be ejected from the metal, the maximum speed of the emitted electrons increases and the stopping potential increases.

Answer:

1.32142x10^-3 Gy

Explanation:

Mass m = 63kg

Time t = 5.0s

Beta energy = 1.5x19^-13J

1 Ci = 3.7x10¹⁰

3.0Ci = 3x3.7x10¹⁰

= 11.1x10¹⁰decay/s

We have a total of 11.1x10¹⁰ beta particles produced per second

The question says there is 100% absorption

Et = (11.1x10¹⁰)x5x1.5x10^-13

= 0.08325

The radiation dose = Et/m

= 0.08325/63 kg

= 0.001321428J/kg

= 0.001321428 grays

Or 1.32142x10^-3 Gy

The radiation dose of the person is 1.31 x 10⁻⁴ J/kg.

The radiation does is the ratio of the total dose to the mass of the person exposed to the radiation.

3 Ci beta radiation = 3 x (3.7x10¹⁰) = 11.1 x 10¹⁰decay/s

Et = (11.1x10¹⁰) x 5 x 1.5 x 10⁻¹³

Et = 8.25 x 10⁻³ J

Radiation dose of the person is calculated as follows;

Rd = Et/m

Rd = (8.25 x 10⁻³ J) / 63

Rd = 1.31 x 10⁻⁴ J/kg

Learn more about radiation dose here: https://brainly.com/question/1421857