Ignore friction. A 20. Lb. Object was lifted to a height of 10 feet by a force of 30. Lb. (a) How much work (ft.Lb) is done by the force? (b) Find the change in potential energy (ft.Lb) of the object

Answer:

mR²/2

Explanation:

Here is the complete question

An object of radius′

R′  and mass ′

M′  is rolling horizontally without slipping with speed ′

V′

. It then rolls up the hill to a maximum height h = 3v²/4g. The moment of inertia of the object is (g= acceleration due to gravity)

Solution

Since it rolls without slipping, there is no friction. So, its initial mechanical energy at the horizontal surface equals its final mechanical energy at the top of the hill.

Since the object is rolling initially, and on horizontal ground, it initial energy is kinetic and made up of rotational and translational kinetic energy.

So, E = K + K'

E = 1/2mv² + 1/2Iω² where m = mass of object, v = speed of object, I = moment of inertia of object and ω = angular speed of object = v/r where v = speed of object and R = radius of object.

Also, the final mechanical energy of the object, E' is its potential energy at the top of the hill. So, E' = mgh.

Since E = E',

1/2mv² + 1/2Iω² = mgh

substituting the values of ω and h into the equation, we have

1/2mv² + 1/2Iω² = mgh

1/2mv² + 1/2I(v/R)²= mg(3v²/4g)

Expanding the brackets, we have

1/2mv² + 1/2Iv²/R²= 3mv²/4

Dividing through by v², we have

1/2m + I/2R²= 3m/4

Subtracting m/2 from both sides, we have

I/2R² = 3m/4 - m/2

Simplifying, we have

I/2R² = m/4

Multiplying through by 2R², we have

I = m/4 × 2R²

I = mR²/2

Answer:

1.it also hleps us to became doctors becuase without physics you can't be a doctor

2.physics needs to be steady whether you like it or not it helps you in life so everybody must study physics no matter is in Uganda USA and plenty more countries there must be physics to dare to be studied

Answer:

Too what i know its because of the air

Explanation:

The steel rod is more dense and doesnt have air whil'st the oil tanker is less dense with lots of air

Answer:

the gas that escaped from the mixture contained the missing weight

Explanation:

The Zeroth Law of Thermodynamics states that if two bodies are each in ... to heat, there will be no transfer of heat from one to the other.

Answer:

It is the inability of the body to change by itself its state of rest or uniform motion or direction. Types of Inertia- It is of three types-(1)Inertia of rest (2) Inertia of motion(3) Inertia of direction. (1) Inertia of rest - It is the inability of the body to change by itself its state if rest.

Answer:

Q. 1. Newton's Law of gravitation states that all bodies in the universe exerts a force of attraction on all other bodies in the universe with a proportional force to both the product of the masses of the bodies and inversely proportional to the square of the distance between their centers

Mathematically, we have;

[tex]F = G \times \dfrac{m_1 \times m_2}{R^2}[/tex]

Where;

m₁, and m₂ are the masses of the bodies

R = The distance between their centers

G = The gravitational constant = 6.6743 × 10⁻¹¹ N·m²/kg²

The gravitational constant, G, is the Newton's law of gravitation's constant of proportionality between the force of attraction that exist two bodies and the product of their masses divided by the square of the distance between their centers

Q. 2. Newton's law of gravitation in vector form is presented as follows;

[tex]\underset{F_{12}}{\rightarrow} = -G \times \dfrac{m_1 \times m_2}{R_{21}^2} \cdot \hat R_{12}[/tex]

The above equation gives the gravitational force of attraction of body 1 on body 2, with the negative sign and unit vector indicating that the force of of gravity is towards body 1

The force of gravity of body 2 on 1 is presented as follows;

[tex]\underset{F_{12}}{\rightarrow} = -G \times \dfrac{m_1 \times m_2}{R_{12}^2} \cdot \hat R_{21}[/tex]

The gravitational force of attraction of body 2 on body 1 is therefore, equal in magnitude and opposite in direction of the gravitational force of body 1 on body 2 (towards body 2)

[tex]-\underset{F_{12}}{\rightarrow} = G \times \dfrac{m_1 \times m_2}{R_{21}^2} \cdot \hat R_{12} = G \times \dfrac{m_1 \times m_2}{R_{21}^2} \cdot -(\hat R_{21}) = -G \times \dfrac{m_1 \times m_2}{R_{21}^2} \cdot \hat R_{21}[/tex]

[tex]-\underset{F_{12}}{\rightarrow} = -G \times \dfrac{m_1 \times m_2}{R_{21}^2} \cdot \hat R_{21} = \underset{F_{21}}{\rightarrow}[/tex]

[tex]-\underset{F_{12}}{\rightarrow} = \underset{F_{21}}{\rightarrow}[/tex]

Explanation:

Answer:

A although am not seeing the cheetah

Answer:

it should be the second option

Explanation:

I can't really see because the picture is kinda blurry

Answer:

the last option.

Explanation:

A body moving with uniform velocity (the flat line, also called the plateau) and then decelerating. The deceleration is why the velocity decreased.

12 x cos 50 = 7.713451316...

Answer:

The wavelength of the photon that would have the same momentum as the electron is 202.2180996 nm

Explanation:

The velocity of the electron, v = 3.6 × 10³ m/s

The momentum of an electron, [tex]p_e[/tex] = m × v

Where;

v = The mass of the electron = 9.109 × 10⁻³¹ kg

∴ [tex]p_e[/tex] = 9.109 × 10⁻³¹ kg × 3.6 × 10³ m/s = 3.27924 × 10⁻²⁷ kg·m/s

According to the de Broglie equation, the momentum of a photon, p, is given as follows;

p = h/λ

Where;

h = 6.63 × 10⁻³⁴ J·s

λ = The wavelength of the photon

∴ λ = h/p

According to the question, we have;

p = [tex]p_e[/tex] = 3.27924 × 10⁻²⁷ kg·m/s

∴ λ = 6.63 × 10⁻³⁴ J·s/(3.27924 × 10⁻²⁷ kg·m/s) = 2.02180993 × 10⁻⁷ m

The wavelength of the photon, λ = 2.02180993 × 10⁻⁷ m = 202.2180993 × 10⁻⁹ m = 202.2180993 nm.

Answer:

divide the density of solution by density of water

EXPLANATION:

LIKE:

1.25÷1000kgm-3

Answer:

Distance, S = 110 meters

Explanation:

Given the following data;

Initial velocity = 15 m/s

Acceleration = 4 m/s²

Time = 5 seconds

To find the distance covered, we would use the second equation of motion;

[tex] S = ut + \frac{1}{2} at^{2} [/tex]

Where;

S is the distance covered or displacement of an object.

u is the initial velocity.

a is the acceleration.

t is the time.

Substituting the values into the equation, we have;

[tex] S = 15*4 + \frac{1}{2} * 4*5^{2} [/tex]

[tex] S = 60 + 2*25 [/tex]

[tex] S = 60 + 50 [/tex]

Distance, S = 110 meters

Answer:

El valor de la fuerza que debe ejercer la persona C debe ser de -2 para que la caja esté en equilibrio físico.

Explanation:

Si la caja debe hallarse en equilibrio físico, entonces se debe satisfacer la siguiente ecuación:

[tex]F_{A} + F_{B} + F_{C} = 0[/tex] (1)

Si sabemos que [tex]F_{A} = -3[/tex] y [tex]F_{B} = 5[/tex], entonces el valor de la fuerza que debe ejercer la persona C debe ser:

[tex]F_{C} = -F_{A}-F_{B}[/tex]

[tex]F_{C} = -(-3)-5[/tex]

[tex]F_{C} = -2[/tex]

El valor de la fuerza que debe ejercer la persona C debe ser de -2 para que la caja esté en equilibrio físico.

Answer:V₁=300ml

T₁=27°C

V₂=?

T₂= -3°C

as we know

V₁T₁=V₂T₂

By putting values in formula

300ml×27°C=V₂×(-3°C)

300ml×27°C/-3°C=V₂

8100ml/-3=V₂

-2700ml=V₂

or V₂=  -2700ml

Answer:

So mass is the amount of matter in an object, but weight is the amount of force that is being applied to your body from gravity.

Mass does not change unless you change your person like your haircut, fingernail length, ect.

Weight changes depending on your mass, because the heavier you are, the stronger the gravitational pull on your person will be, which increases your weight.

That is why if you go onto the moon, for example, your weight is different, since the gravitational pull is weaker than on Earth, so you weigh less.

Explanation:

Answer:

Insulation.

Explanation:

A calorimeter can be defined as a scientific instrument or device designed and developed for measuring the heat involved in reactions or other processes, especially by taking the measurement of the temperature of the materials surrounding the process.

Basically, a calorimeter is insulated using materials with very high level of resistivity so as to prevent heat transfer to the outside of the device (calorimeter).

This ultimately implies that, insulation of cylindrical vessel prevents the transfer of heat into or out of the calorimeter.

Answer:

Explanation:

[tex]\lambda\\[/tex] = v/f

^That is the formula we are going to use.

Now, we were given the speed (v), which is 20.

Now we need to find frequency, in order to solve for the wavelength.

Frequency is the amount of waves in a fixed unit of one second, meaning our F value is the value of 5 divided by 4.

5/4 = 1.25

Therefore our F is 1.25

Now lets plug it in

[tex]\lambda\\[/tex] = v/f

[tex]\lambda\\[/tex] = 20/1.25

[tex]\lambda\\[/tex] = 16

Conversion:

[tex]\lambda\\[/tex] = 8

Answer:

A = 2.4 A

[tex]R_{eq} = 5 \ \Omega[/tex]

Explanation:

The voltage in the circuit, V = 12 V

The given circuit shows four resistors with R₁ and R₂ arranged in series with both in parallel to R₃ and R₄ which are is series to each other

R₁ = 4 Ω

R₂ = 6 Ω

R₄ = 5 Ω

The voltage across R₃ = 6 V

Voltage across parallel resistors are equal, therefore;

The total voltage across R₃ and R₄ = 12 V

The total voltage across R₁ and R₂ = 12 V

The voltage across R₃ + The voltage across R₄ = 12 V

∴ The voltage across R₄ = 12 V - 6 V = 6 V

The current flowing through  R₄ = 6V/(5 Ω) = 1.2 A

The current flowing through R₃ = The current flowing through R₄ = 1.2 A

The resistor, R₃ = 6 V/1.2 A = 5 Ω

Therefore, we have;

The sum of resistors in series are R₁ + R₂ and R₃ + R₄, which gives;

[tex]R_{series \, 1}[/tex] = R₁ + R₂ = 4 Ω + 6 Ω = 10 Ω

[tex]R_{series \, 2}[/tex] = R₃ + R₄ = 5 Ω + 5 Ω = 10 Ω

The sum of the resistors in parallel is given as follows;

[tex]\dfrac{1}{R_{eq}} = \dfrac{1}{R_{series \, 1}} + \dfrac{1}{R_{series \, 2}} = \dfrac{R_{series \, 2} + R_{series \, 1}}{R_{series \, 1} \times R_{series \, 2}}[/tex]

Therefore;

[tex]R_{eq} = \dfrac{R_{series \, 1} \times R_{series \, 2}}{R_{series \, 1} + R_{series \, 2}}[/tex]

Therefore;

[tex]R_{eq} = \dfrac{10\times 10}{10 + 10} \ \Omega = 5 \ \Omega[/tex]

[tex]R_{eq} = 5 \ \Omega[/tex]

The value of the current, A, in the circuit, I = V/[tex]R_{eq}[/tex]

A = I = 12 V/(5 Ω) = 2.4 A

A = 2.4 A

Answer:

6.86 × 10²⁴ kg

Explanation:

The mass of the earth m = density of earth, ρ × volume of earth, V

m = ρV

The density of the earth, ρ = 5515 kg/m³ and since the earth is a sphere, its volume is the volume of a sphere V = 4πr³/3 where r = radius of the earth = 6.67 × 10⁶ m

Since m = ρV

m = ρ4πr³/3

So, substituting the values of the variables into the equation for the mass of the earth, m, we have

m = 5515 kg/m³ × 4π(6.67 × 10⁶ m)³/3

m = 5515 kg/m³ × 4π × 296.741 × 10¹⁸ m³/3

m = 5515 kg/m³ × 1189.9639π × 10¹⁸ m³/3

m = 6546105.64378π × 10¹⁸ kg/3

m = 20565197.400122 × 10¹⁸ kg/3

m = 6855065.8 × 10¹⁸ kg

m = 6.8550658 × 10²⁴ kg

m ≅ 6.86 × 10²⁴ kg

Answer:

La materia es la sustancia de la que está hecho todo material. En física, el sistema es una de las propiedades de la materia. Se puede transferir entre objetos y convertir en forma. No se puede crear ni destruir.

espero que te ayude!

The question is incomplete, the complete question is;

Water has a specific heat of 4.186 J/g°C, and ethanol has a specific heat of 2.450 J/g°C. Based on this information, which best compares water and ethanol?

It requires more heat to raise the temperature of a gram of ethanol by 1°C.

There are more molecules in a gram of water.

Ethanol has a lower formula mass.

Water has more protons and neutrons in its nuclei.

Answer:

There are more molecules in a gram of water.

Explanation:

Let us recall that the molar mass of water is 18g/mol while the molar mass of ethanol is 46 g/mol.

Hence;

1 g of water contains 18 g

There are 6.02 × 10^23/18g = 3.34 × 10^22 molecules in 1 g of water

1 g of ethanol contains 46 g

There are 6.02 × 10^23/46 g = 1.31 ×10^22 molecules

Hence, there are more molecules in 1 g of water than in 1g of ethanol.

Answer:

there are more molecules in 1 g of water than in 1g of ethanol.

Explanation:

edge 23

Answer:

Explanation:

We are basically needing to solve for the time in the equation d = rt, where d is the distance around Mars (aka the circumference), r is the velocity, and t is time. We need to find the circumference and the velocity. We will begin with the velocity.

Because the gravitational attraction between Phobos and Mars provides the centripetal acceleration necessary to keep Phobos in its (sort of) circular path, the equation we use for this is:

[tex]F_g=F_c[/tex] which says that Force supplied by gravity is equal to the centripetal force. Expanding that:

[tex]\frac{Gm_{Phobos}m_{Mars}}{r^2}=\frac{m_{Phobos}v^2}{r}[/tex]

When we move that around mathematically to solve for the velocity value, what we end up with is:

[tex]v=\sqrt{\frac{Gm_{Mars}}{r}[/tex] and filling in:

[tex]v=\sqrt{\frac{(6.67*10^{-11})(6.42*10^{23})}{9.38*10^6} }[/tex] and we get that

v = 2100 m/s

Now for the circumference:

C = 2πr and

C = 2(3.1415)(9.38 × 10⁶) so

C = 5.9 × 10⁷

Putting that all together in the C = vT equation:

5.9 × 10⁷ = 2100T so

T = 2.8 × 10⁴ sec or 7.8 hours

Answer:

Friction is caused in roller coasters by the rubbing of the car wheels on the track and by the rubbing of air (and sometimes water!) against the cars.

Explanation:

Answer:

Explanation:

Givens

t = 10 seconds

vi = 0

vf = 3600 mph

a = ?

d = 10000 feet

Formula

a = (vf - vi)/t

Solution

vf = 3600 mph * 1 hr / 3600 seconds * 5280 feet / 1 mile = 5280 ft / sec

a = (5280 - 0)/10

a = 528 ft/sec^2

Answer:

a. Energy lost, Q = 16,800 Joules.

b. Power = 28 J/s

c. Time, t = 2357.14 seconds

d. I assumed that the ice remained at a temperature of zero degrees Celsius (0°C). Also, I assumed that the heat is being lost at a constant rate.

Explanation:

Given the following data;

a. To find the energy lost by the water as it cools to 0 degree celsius;

Mathematically, heat capacity is given by the formula;

[tex] Q = mcdt [/tex]

Where;

dt = T2 - T1

dt = 20 - 0

dt = 20°C

We know that the specific heat capacity of water is equal to  4200 J/kg°C

Substituting the values into the formula, we have;

[tex] Q = 0.20 * 4200 * 20 [/tex]

Energy lost, Q = 16,800 Joules.

b. To find the average rate at which the water is losing energy in J/s by using the following formula;

[tex] Power = \frac {energy}{time} [/tex]

First of all, we would have to convert the value of time in minutes to seconds.

Conversion:

1 minute = 60 seconds

10 minutes = X seconds

Cross-multiplying, we have;

X = 60 * 10

X = 600 seconds

Substituting the values into the formula, we have;

[tex] Power = \frac {16800}{600} [/tex]

Power = 28 J/s

c. To estimate the time taken for the water at 0 degree celsius to turn completely into ice;

We know that the latent heat of fusion of water is equal to 3.3 * 10⁵ J/kg.

Mathematically, the latent heat of fusion is calculated by using the formula;

Energy, Q = ml = pt

Substituting the values into the formula, we have;

0.20 * 3.3 * 10⁵ = 28 * t

0.20 * 330000 = 28t

66000 = 28t

[tex] t = \frac {66000}{28} [/tex]

Time, t = 2357.14 seconds.

d. The assumption made is that, the ice remained at a temperature of zero degrees Celsius (0°C). Also, I assumed that the heat is being lost at a constant rate.

Answer:

condensation - thermal energy removed

freezing -thermal energy removed

deposition - thermal energy removed

sublimation - thermal energy added

evaporation - thermal energy added

melting - thermal energy added

Explanation:

Thermal energy is heat energy. Processes in which heat is added involve the addition of thermal energy while processes in which heat energy is removed involves removal of thermal energy.

Condensation involves a change from gas to liquid, freezing involves a change from liquid to solid while deposition involves the settling of mobile particles at a place. All these processes involve a decrease in energy of particles.

On the other hand, sublimation is a direct change from solid to gas, melting involves a change from solid to liquid while evaporation involves a change from liquid to gas. All these processes occur when energy is added to the particles in a system.

Answer:

condensation - thermal energy removed

freezing -thermal energy removed

deposition - thermal energy removed

sublimation - thermal energy added

evaporation - thermal energy added

melting - thermal energy added

The pascal is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength.