any correct ans guess for 30 pts and brainlist​

Answer:

800N

Explanation:

as we know that

weight = mass × acceleration due to gravity

= 80kg × 10 m/s^2

= 800N.

Answer:

(i)  Electric field outside the shell:

For point r>R; draw a spherical gaussian surface of radius r.

Using gauss law, ∮E.ds=q0qend

Since E is perpendicular to gaussian surface, angle betwee E is 0.

Also E being constant, can be taken out of integral.

So, E(4πr2)=q0q

So, E=4πε01r2q

Answer:

Take water as an example; the size, shape and chemical composition of the water particles remains the same whether it is solid water (ice) or gaseous water (steam) - but how those particles move and are arranged is different for

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:

The speed of the train when the tail buffers pass the lamp post is 9 m/s

Explanation:

The given parameters are;

The length of the train = 90 m

The initial velocity of the train, u = 0

The average acceleration of the train, a = 0.45 m/s²

When the tail buffer pass the lamp post, P, we have;

The distance travelled, s = The length of the train = 90 m

The kinematic equation of motion is given as follows;

v² = u² + 2·a·s

Where;

v = The speed of the train when the tail buffers pass the lamp post

∴ v² = 0² + 2 × 0.45 m/s² × 90 m = 81 m²/s²

Therefore;

v = √(81 m²/s²) = 9 m/s

The speed of the train when the tail buffers pass the lamp post, v = 9 m/s.

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:

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:

contains many individual light detectors, each with its own lens

Explanation:

The compound eye is found mainly in insects and crustaceans, it is composed of individual receptor units, each with its focus, sensing nerve; each one gives a small image of the environment, so the image is mosaic type, not a complete integral image of the environment.

When reviewing the different statements, the correct one is

contains many individual light detectors, each with its own lens

Answer:

Power = I * V = 2.5 C/s * 5 J/C = 12.5 J/s = 12.5 watts

Regardless of the efficiency the power consumed is that used by the converter.

E = P * t = 12.5 J/s * 4500 s = 4500 J

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:

Pressure and velocity are inversely proportional to each other because if pressure increase, the velocity decrease to keep the algebraic sum of potential energy, kinetic energy and pressure constant.

Answer:

Distance = 6.667 kilometres

Explanation:

Given the following data;

Speed = 20 km/h

Departure time = 7:00

Arrival time = 7:20

Time taken = 20 minutes

To calculate the distance travelled from home to school;

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

Conversion:

60 minutes = 1 hour

20 minutes = X hours

Cross-multiplying, we have;

X = 20/60 = 1/3 hours

Mathematically, the distance travelled by an object is calculated by using the formula;

Distance = speed * time

Distance = 20 * 1/3

Distance = 20/3 =

Distance = 6.667 kilometres

Answer:

1) Motion of air mass moving from equator northward (closer to earth axis)

2) Motion of object in orbit

3) Collision of 2 objects

4) Skater changing rotation by extension of arms

5) Motion of rocket due to velocity of expelled gas

Answer:

i. The pressure of due to the water, P, is given according to the following equation;

P = ρ·g·h

Where;

ρ = The density of the water (a constant) = 997 kg/m³

g = The acceleration due to gravity = 9.81 m/s²

h = The height of the water (minimum h = h₁, maximum h = h₂)

The pressure is directly proportional to the water height, and we have;

The pressure, P, will be maximum when the water height, h, is maximum or h = h₂, which is the level DC

ii. The thrust = The force acting on the body = Pressure × Area

The maximum areas exposed to the water are on side AB and DC

However, the pressure at level DC, which is the location of the maximum pressure, is larger than the pressure at level AB, therefore, the maximum thrust will be at the level DC

Explanation:

Answer:

B - Only a concentration of mass in the nucleus could explain the deflection of the incident particles.

Answer:

MgO relative atomic mass is 40

Explanation:

Mg=24

O=16

Answer:

A. When the independent variable is continuous and shows a causal link to the dependent variable.

Explanation:

A graph can be defined as the graphical representation of data (informations) on horizontal and vertical lines i.e x-axis and y-axis respectively.

In an experiment , the variable being manipulated by an experimenter is known as an independent variable while the dependent variable is the event expected to change when the independent variable is manipulated

Generally, a line graph should be used when the independent variable is continuous and shows a causal link to the dependent variable.

This ultimately implies that, a line graph should be used when the data changes continuously over time and as such there exist a linear relationship between the data (variables).

Answer:1

Explanation:1

Answer:

The motion of the moon around the earth is circular motion

Explanation:

Answer:

4360 Kgm/s

Explanation:

Applying,

Ft = M-M'................. Equation 1

Where F = force, t = time, M = Final momentum, M' = Initial momentum.

make M the subject of the equation

M = Ft+M'............ Equation 2

From the question,

Given: F = 4000 N, t = 0.9 seconds, M' = 400 kg-m/s

Substitute these values into equation 2

M = 4000+(0.9×400)

M = 4000+360

M = 4360 kgm/s

Hence the final momentum is 4360 kgm/s

Answer:

A) How the size of a tree affect the bird species that prefer to live in it

Explanation:

I took the quiz

The answer is definitely Potassium

Answer:

no is the most expensive but u have

Answer:

Explanation:

Here,

Final mass(m)=150g

Final Temperature(t)=60°C

Temperature of hot water(t1)=90C

Temperature of cold water(t2)=14C

Let the grams of water to be used per face be m1 grams and (150-m1) grams for hot and cold water respectively.

We know that,

Heat lost by hot body=Heat gained by cold body

or, m1 s1 Δt1=m2 s2 Δt2

or, m1 (t1-t)=(150-m1) (t-t2)  [∵s1=s2, SHC of water is taken to be same]

or, m1 (90-60)=(150-m1) (60-14)

or, 30m1=6900-46m1

or, 76m1=6900

∴m1=90.79g

(150-m1)=59.21g

Hence, 90.79g and 59.21 g hot and cold water must be used respectively.

Answer:

Velocity is the speed of something given in a direction. the SI unit of velocity is metre per second or m/s.

Answer:

A although am not seeing the cheetah

Answer:

6x+8=32

6x=32-8

6x=24

x=24:6

x= 4

vậy, x =4