1. If you use an applied force of 45N to slide a 12Kg wooden crate across a floor at a constant velocity, what is the coefficient of kinetic friction between the crate and the floor?

Answer:

B - Person A's chair rolls backwards.

Explanation:

This can be seen simply through the Conservation of Momentum. When the ball is thrown to be, the ball's momentum(+m) is transfererd to B, so B's chair moves forward(think about it - it makes sense, doesn't it?), meaning A's chair moves backwards.

So, B.

EXTRA TIP: Try drawing a diagram to help you!  

Answer:

The velocity with which the sand throw is 24.2 m/s.

Explanation:

acceleration due to gravity, a =  3.9 m/s2

height, h = 75 m

final velocity, v = 0

Let the initial  velocity at the time of throw is u.

Use third equation of motion

[tex]v^{2} = u^{2} - 2 g h \\\\0 = u^{2} -2\times 3.9\times 75\\\\u=24.2m/s[/tex]

The velocity with which the sand throw is 24.2 m/s.

Answer:

Cardboard, Paper towels, Food waste, and wooden based items

Answer:

How fast do things biodegrade?

Vegetables 5 days –1 month

Aluminium cans 80–100 years

Glass bottles 1 million years

Styrofoam cup 500 years to forever

Plastic bags 500 years to forever

Answer:

the correct answer is B

Explanation:

The law of reflection states that the angles of incidence and reflection on a surface are the same, the two rays and the normal are in the same part of the surface.

In this exercise indicate that the angle between the incident and reflected ray is 10, therefore the angle with respect to the normal that is a vertical line at the point of contact of the ray must be 5

Consequently the correct answer is B

Answer:

a.  9.99625 cm b. 68 °C

Explanation:

(a) What is the length of the rod at the freezing point of water (0 0C)?

Before we find the length of the rod, we need to find the coefficient of linear expansion, α = (L - L₀)/[L₀(T - T₀)] where L₀ = length of rod at temperature T₀ = 10.0 cm, T₀ = 20 °C, L = length of rod at temperature T = 10.015 cm and T = 100 °C

Substituting the values of the variables into the equation, we have

α = (L - L₀)/[L₀(T - T₀)]

α = (10.015 cm - 10.0 cm)/[10.0 cm(100 °C - 20 °C)]

α = 0.015 cm/[10.0 cm × 80 °C]

α = 0.015 cm/[800.0 cm °C]

α = 0.00001875 /°C

We now find the length L₁ at T₁ = 0 °C from

L₁ = L₀(1 + α(T₁ - T₀))

So, substituting the values of the variables into the equation, we have

L₁ = L₀(1 + α(T₁ - T₀))

L₁ = 10.0 cm[1 +  0.00001875 /°C(0° C - 20 °C)]

L₁ = 10.0 cm[1 +  0.00001875 /°C × -20° C]

L₁ = 10.0 cm[1 - 0.000375]

L₁ = 10.0 cm[0.999625]

L₁ = 9.99625 cm

(b) What is the temperature if the length of the rod is 10.009 cm?

With length L₃ = 10.009 cm at temperature T₃, using

L₃ = L₀(1 + α(T₃ - T₀))

making T₃ subject of the formula, we have

L₃/L₀ = 1 + α(T₃ - T₀)

L₃/L₀ - 1 = α(T₃ - T₀)

T₃ - T₀ = (L₃/L₀ - 1)/α

T₃ = T₀ + (L₃/L₀ - 1)/α

substituting the values of the variables into the equation, we have

T₃ = 20 °C + (10.009 cm/10.0 cm - 1)/0.00001875 /°C

T₃ = 20 °C + (1.0009 - 1)/0.00001875 /°C

T₃ = 20 °C + 0.0009/0.00001875 /°C

T₃ = 20 °C + 48 °C

T₃ = 68 °C

Answer:

No.

Explanation:

A feather is less dense and thus less force exerted while a rock is very dense thus exerting more force .

Answer:

Solution given:

strength of electric field [E]:?

distance[d]:0.2m

charge[Q]=[tex]1.56×10^{-6} C[/tex]

we have

E =K [tex] \frac{Q}{r²}[/tex]

E=[tex]9×10^{9} C[/tex][tex] \frac{1.56×10^-6 C}{0.2²} [/tex]

E=[tex] 3.51×10^{5}[/tex]V/m

strength of electric field : [tex] 3.51×10^{5}[/tex]V/m

Answer:

Thus, the time for the first lamp is 44 minutes.

Explanation:

Power of first lamp, P' = 1000 W

Power of second lamp, P'' = 4400 W

time for second lamp, t'' = 10 minutes

Let the time for first lamp is t'.

As the energy is same, so,

P' x t' = P'' x t''

1000 x t' = 4400 x 10

t' = 44 minutes

Answer:

Explanation:

We will use the KE equation you wrote here and fill in what we are given:

[tex]36=\frac{1}{2}m(12)^2[/tex] and isolating the m:

[tex]m=\frac{2(36)}{12^2}[/tex] which gives us

m = .50 kg

Answer:

1. [tex]h = 244.8 m[/tex]    

2. [tex]x = 564.8 m[/tex]  

Explanation:

1. La altura máxima se puede calcular usando la siguiente ecuación:

[tex] v_{f}^{2} = v_{0}^{2} - 2gh [/tex]     (1)                        

Where:

[tex]v_{f_{y}}[/tex]: es la velocidad final = 0 (en la altura máxima)  

[tex]v_{0_{y}}[/tex]: es la velocidad inicial horizontal en "y"

g: es la gravedad = 9.81 m/s²          

h: es la altura máxima =?

La velocidad incial en "y" se puede calcular de la siguiente manera:

[tex] tan(\theta) = \frac{v_{0_{y}}}{v_{0_{x}}} [/tex]

[tex] v_{0_{y}} = tan(60)*40 m/s = 69.3 m/s [/tex]                    

Resolviendo la ecuación (1) para "h" tenemos:

[tex]h = \frac{v_{0_{y}}^{2}}{2g} = \frac{(69.3 m/s)^{2}}{2*9.81 m/s^{2}} = 244.8 m[/tex]          

2. Para calcular el alcance horizontal podemos usar la ecuación:

[tex]x = v_{x}*t[/tex]

Primero debemos encontrar el tiempo cuando la altura es máxima ([tex]v_{f_{y}}[/tex] = 0).

[tex] v_{f_{y}} = v_{0_{y}} - gt [/tex]    

[tex] t = \frac{v_{0_{y}}}{g} = \frac{69.3 m/s}{9.81 m/s^{2}} = 7.06 s [/tex]      

Ahora, como el tiempo de subida es el mismo que el tiempo de bajada, el tiempo máximo es:

[tex] t_{m} = 2*7.06 s = 14.12 s [/tex]          

Finalmente, el alcance horizontal es:

[tex]x = 40 m/s*14.12 s = 564.8 m[/tex]                                                            

Espero que te sea de utilidad!

Answer:

A) terminal moraines

Explanation:

Moraines are the rocks and sediments deposited by moving glaciers. Terminal means the end, the furthest the glacier travels. Lateral means what's deposited along the sides of the moving glacier.

Answer:Chemical energy

Explanation:, Energy stored in the bonds of chemical compounds. Chemical energy may be released during a chemical reaction, often in the form of heat; such reactions are called exothermic.

Answer:

Hope this helps

Explanation:

Chemical energy, Energy stored in the bonds of chemical compounds Chemical energy may be released during a chemical reaction, often in the form of heat such reactions are exothermic. The chemical energy in food us converted by the body into mechanical energy and heat .

Answer:

chonks of rock will hit the earth and if one astoroid is big enough it can distroy all liofe on earth

Explanation:

Answer:

If we nuke the moon, it won't have any sound and will quickly be stopped from travelling any further than the place we nuked it. If some parts of the moon crack and break, it will be forced down on us (like an asteroid).

Many possibilities can happen but I'm just listing one of them.

Answer:

k = 933.88 N/m

Explanation:

Given that,

The mass of a load, m = 8.1 kg

The displacement in the spring, x = 8.5 cm

We need to find the force constant of the spring. We know that Hooke's law is given by :

F = -kx

Also,

F = mg (Force due to its weight)

So,

[tex]k=\dfrac{mg}{x}\\\\k=\dfrac{8.1\times 9.8}{0.085}\\\\k=933.88\ N/m[/tex]

So, the force constant of the spring is equal to 933.88 N/m.

Answer:

Explanation:

During an earthquake, there are both transverse and longitudinal wave. The answer is c.

Answer:

Explanation:

ans is c. Both transverse and longitudinal

Answer:

271 K

Explanation:

Answer:

The temperature of Nitrogen is 270.85 K.

Explanation:

A gas that follows Boyle's law , Charle's law and law of pressure , is called perfect gas.

Given data;

[tex]P =101.3 KPa , V = 0.08 m^{3} , \\ n = 3.6 mol , R = 8.31\\T = ?[/tex]

By the formula,

P.V = n .R.T

On putting values

[tex]1.013[/tex] x [tex]10^{5}[/tex] x [tex]0.08[/tex] = [tex]3.6[/tex] x [tex]8.31[/tex] x [tex]T[/tex]

So [tex]T =\frac{1.013*10^{5} * 0.08}{3.6 * 8.31}[/tex]

 [tex]T =\frac{8104}{29.92}[/tex]

[tex]T = 270.85 K[/tex]

Hence the temperature of Nitrogen is 270.85 K

For more details also read -

https://brainly.com/question/12744632?referrer=searchResults

#SPJ2

Explanation:

.Flame retar,dant plastic additi,ves are compounds added to plastics and other materials to inhibit, suppress or de,lay combustion. These compounds are useful in impending burning in the ign,ition phase of fire. They do not prevent char,ring or melting nor do they increase the heat resistance of a material

4 N to right

( the third option )

...................................

Answer:

I'm pretty sure its C

Explanation:

Answer:

Option D

Explanation:

The options for the question are

a) How do galaxies rotate?

b) What is the weather on Neptune?

c) What is the core of Saturn made of?

d) What other solar systems have planets?

Solution

The Hubble space telescope was designed and integrated into the extraterrestrial system in order to capture information about the surrounding universe. If the  Keck Observatory has a better observation capacity than the Hubble space telescope then the scientist would be interested to know the surrounding planets in the solar system.

Hence, option D is correct

Answer:

The magnetic field will help to create an electromagnetic radiation which will prevent the charged particle from moving in a constant direction in a straight path.

Explanation: A magnetic field is an area around a particle where magnetic energy is felt or experienced, this ensures that all the charged particle within the magnetic field will be influenced by magnet.

In the highlighted situation, the magnetic field will help to ensure that an electromagnetic radiation is created to synchrotron radiation occurs effectively.

Answer:

[tex]31.6\:\mathrm{m/s}[/tex]

Explanation:

The elastic potential energy of a spring is given by [tex]Us=\frac{1}{2}kx^2[/tex], where [tex]k[/tex] is the spring constant of the spring and [tex]x[/tex] is displacement from point of equilibrium.

When released, this potential energy will be converted into kinetic energy. Kinetic energy is given by [tex]KE=\frac{1}{2}mv^2[/tex], where [tex]m[/tex] is the mass of the object and [tex]v[/tex] is the object's velocity.

Thus, we have:

[tex]Us=KE,\\\frac{1}{2}kx^2=\frac{1}{2}mv^2[/tex]

Substituting given values, we get:

[tex]\frac{1}{2}\cdot 50\cdot 0.2^2=\frac{1}{2}\cdot 0.002\cdot v^2,\\v^2=\frac{50\cdot 0.2^2}{0.002},\\v^2=1000,\\v\approx \boxed{31.6\:\mathrm{m/s}}[/tex]

If you are not advised to evacuate or are unable to do so safely, stay indoors, away from windows, skylights and doors. Continue to monitor weather reports and do not go outside until the storm has passed. And, to protect your children from seeing too many sights and images of the hurricane, limit media exposure.

top ( 25 m ) | 75000 j | 0 j | 75000 j

-------------------|---------------|------------|-------------

bottom ( 0 ) | 0 j | 75000j | 75000 j

-------------------|---------------|------------|-------------

h d ( 12.5 m ) | 37500 j | 37500j | 75000 j

-------------------|---------------|------------|-------------

f d ( 5 m ) | 15000 j | 60000j | 75000 j

-------------------|---------------|------------|-------------

Answer:

Average speed = 53.33 km/h

Explanation:

Below is the calculation for the average speed:

Given the average speed of for first 40 km = 80km/h

Time taken to cover the first 40 km = Total Distance / average speed

Time taken to cover the first 40 km = 40 / 80 = 0.5 hours

Given the average speed of for next 40 km = 40km/h

Time taken to cover the next 40 km = Total Distance / average speed

Time taken to cover the next 40 km = 40 / 40 = 1 hours

Now the average speed of the tuck to cover total distance:

Average speed = Total distance / Total time

Average speed = (40 + 40) / (0.5 + 1)

Average speed = 53.33 km/h

Answer:

Impulse = 50,000 J

Explanation:

Given: force = 100,000 kg ms^2 or N; time = 0.5 s

Unknown: impulse = ?

Equation: impulse = (force)(time)

Substitute: impulse = (100,000 kg ms^2 or N)(0.5 s)

Solution: impusle = 50,000 kg ms^2 or J

Answer:

The given potential energy of the spring is expressed as follows;

ΔUsp = -(WB + WW)

Where;

WB = Th work done by the spring on the block to which it is attached

WW = The work done by the spring on the wall

We recall that work done, W = Force applied × Distance moved in the direction of the force

The work done by the spring on the block, WB = The spring force × The distance the block moves

The work done by the spring on the wall, WW = The spring force × The distance the wall moves

However, given that the wall does not move, we have;

The distance the wall moves = 0

∴ The work done by the spring on the wall, WW = The spring force × 0 = 0 J

Therefore, WW = 0 J, and the spring does not do work on the wall, and WW can be ignored in the next subsequent) steps

Explanation:

Answer:

Explanation:

Magnitude of frictional force = μ mg

μ is either static or kinetic friction.

To start the crate moving , static friction is calculated .

a ) To start crate moving , force required = μ mg where μ is coefficient of static friction .

force required =.517 x 56.6  x 9.8 = 286.76  N .

b ) to  slide the crate across the dock at a constant speed , force required

= μ mg where μ is coefficient of kinetic  friction , where μ is kinetic friction

= .26 x 56.6  x 9.8 = 144.21 N .