A rocket of mass M when empty carries a mass M of fuel. The rocket and fuel travel at speed v.
The engine of the rocket is fired and all of the fuel is expelled. The speed of the rocket increases
to 2v.

What happens to the kinetic energy of the rocket?
A It doubles.
B It halves.
C It increases by a factor of four.
D It stays the same.

Answer:

P = 2.33 kW

Explanation:

Given that,

Mass, m = 200 kg

It is raises in the well from a depth of 7 m in 6 s.

W e know that,

Power = work done/time

Put all the values,

[tex]P=\dfrac{mgh}{t}\\\\P=\dfrac{200\times 10\times 7}{6}\\\\P=2333.3\ W[/tex]

or

P = 2.33 kW

Hence, the power of the engine is 2.33 kW.

Answer:

• Go Native. Use native plants in your landscape. ...

• Reduce Chemical Use. Use fewer chemicals around your home and yard, and make sure to dispose of them properly - don't dump them on the ground!

• Manage Waste. ...

Explanation:

There are some easy ways to conserve water to help protect our aquifers, watersheds, and ground water. First, we can all conserve water, by not running the water while we brush our teeth and making sure we fix all leaking or dripping faucets. Another was to conserve water is to collect rain water to use to water your plants. Speaking of plants, you can also plant more zeroscape type landscapes that require less water. We can also update our shower heads and toilets to be low-flow and more efficient. Can't afford a new toilet? Simply add a brick to your tank and this will cut down on the water used for every flush.

Answer:

Explanation:

Hooke's Law is a linear representation that, in equation form, looks like this:

F = -kΔx where F is force, k is the spring constant, and Δx is the displacement of the spring when a Force is applied to it in the form of a mass hanging on the end of it. We need to use the equation to solve for the spring constant, k. Doing this by filling in the values we were given:

4 = -k(-12) the 12 is negative because the mass hangs below the point of equilibrium. This gives us that

k = 1/3. Now we'll use that in the next equation where we need to solve for displacement:

6 = -1/3(Δx) and

Δx = -18 cm

Answer:

Option a

Explanation:

Answer:

Rest and motion are the relative terms.

Explanation:

When the position of the object does not change with respect to time, the object is said to be at rest.

When the position of the object changes with respect to time, the object said to be in motion.

let there is a tree, the tree is at rest with respect to the person which is standing near by the tree.

But when the person is in outer space and able to see the tree, the tree is in motion as the earth is in  motion.

A person sitting in the train which is moving is at rest when observed by the other person sitting in the train but he is in motion with respect to a person which is standing on the platform.  

Answer:

4.88 K.

Explanation:

From the question given above, the following data were obtained:

Number of mole (n) = 5 moles

Pressure (P) = 1 atm

Volume (V) = 2 L

Gas constant (R) = 0.082 atm.L/Kmol

Temperature (T) =?

The temperature of the gas can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

1 × 2 = 5 × 0.082 × T

2 = 0.41 × T

Divide both side by 0.41

T = 2 / 0.41

T = 4.88 K

Therefore, the temperature of the gas is 4.88 K.

Answer:

The correct answer is - none of the above.

Explanation:

Cell membranes or plasma membranes of the cell are composed mainly of fatty-acid-based lipids and proteins. Membrane lipids are of two types majorly, glucolipids, phospholipids, and sterols (generally cholesterol).

Sphingolipids are also a structural component of the cell membrane that helps in segregation into distinct membrane domains. Glycolipids are present on the surface of the plasma membrane.

Answer:

Explanation:

If the surface area of an object is smaller, it will create more pressure

An object's surface area is inversely proportional to its pressure.

This can be demonstrated from the formula below

The can be defined as the perpendicular force acting per unit area. the S.I  unit of pressure is N/m².

In View of the above equation, It can be seen that as the surface area of an object reduces the pressure created by the object will increase.

Hence, If the surface area of an object is smaller, it will create more pressure

Learn more about pressure here: https://brainly.com/question/25736513

Answer:

45 m/s

Explanation:

162 / 3.6 = 45 m/s

Divide by 3.6 to convert km/h to m/s.

Answer:

a) 72 europeos viajan en el avión, b) 132 pasajeros viajan en el avión, c) Hay una proporción de 3 africanos a 5 americanos en el avión.

Explanation:

a) Si 30 % son asiáticos, 15 % africanos y 25 % americanos, entonces 30 % son europeos. La cantidad de europeos en el avión es:

[tex]x = 0.3\cdot (240)[/tex]

[tex]x = 72[/tex]

72 europeos viajan en el avión.

b) El total de asiáticos y americanos en el avión se determina mediante la siguiente expresión:

[tex]x = (0.3 + 0.25)\cdot (240)[/tex]

[tex]x = 132[/tex]

132 pasajeros viajan en el avión.

c) En primer lugar, se calculan los números de africanos y americanos en el avión:

Africanos

[tex]x_{1} = 0.15\cdot (240)[/tex]

[tex]x_{1} = 36[/tex]

Americanos

[tex]x_{2} = 0.25\cdot (240)[/tex]

[tex]x_{2} = 60[/tex]

Y la razón de viajeros africanos a viajeros americanos es:

[tex]r = \frac{r_{1}}{r_{2}}[/tex]

[tex]r = \frac{36}{60}[/tex]

[tex]r = \frac{3}{5}[/tex]

Hay una proporción de 3 africanos a 5 americanos en el avión.

Answer:

See Explanation

Explanation:

Convection is a mode of heat transfer which involves the actual movement of the particles of a substance.

The hotter particles move upwards and are replaced by the cooler particles, thus a convection current is set up. This is due to the fact that cooler particles are denser than warmer particles.

Warm magma is found far beneath the earth. It rises to the surface due to convection current thereby leading to volcanos. Volcanic eruptions result from convection currents that occur underground.

Answer:

Increase in frequency constantly

Explanation:

This concept can be explained by Doppler shift as per which any form of disturbance spreads out spherically from its point of origin. If the source of sound wave is stationary and the receiver is also stationary, then the frequency remains the same but if the source is moving, then the disturbance caused is closer on one side and distant on the other side thereby producing shorter wavelength in direction the source is moving and longer wavelength in the opposite direction.

Answer:

2. the volume of the square are the same

Answer:

the volume of the squares are the same

Explanation:

Answer:

pretty sure its A hope this helped

Answer:

the answer is  tree

Explanation:

because tree is made up of woodly barks and not atoms so we can say that tree is the answer. u may wander, why not hear or baloon cause heat is a gas state which is made up of atom and baloon contains gall like helium which is also made up of atom.

hope this helps u

Answer:

work

Explanation:

it is a scalar quantity. it is equal to product of force and distance if the direction of motion is in direction of force in straight line

Answer:

work

Explanation:

:>)

Answer:

a10

Explanation:

Answer:

180 Newton(N)

Explanation:

force =mass *acceleration

=60 * 3

=180 kgm/s^2

=180 N

Answer:

[tex]E=5\times 10^{-5}\ J[/tex]

Explanation:

Given that,

A spring is compressed by 0.1 cm or 0.001 m

The spring constant of the spring, k = 100 N/m

The elastic potential energy in the spring is given by :

[tex]E=\dfrac{1}{2}kx^2\\\\E=\dfrac{1}{2}\times 100\times 0.001^2\\\\E=5\times 10^{-5}\ J[/tex]

So, the elastic potential energy of the spring is equal to [tex]5\times 10^{-5}\ J[/tex].

Answer:

the final pressure of the gas is 60 kPa.

Explanation:

Given;

initial pressure of the gas, P₁ = 50 kPa = 50,000 Pa

initial temperature of the gas, T₁ = 27⁰ C = 27 + 273 = 300 k

final temperature of the gas, T₂ = 87⁰ C = 87 + 273 = 360 K

Let the final pressure of the gas = P₂

Apply pressure law;

[tex]\frac{P_1}{T_1} = \frac{P_2}{T_2} \\\\P_2 = \frac{P_1T_2}{T_1} = \frac{50,000 \times 360}{300} = 60,000 \ Pa = 60 \ kPa[/tex]

Therefore, the final pressure of the gas is 60 kPa.

Given : Airplane is 0.68 kilometers long

We know that :

⊕   1 km = 1000 meters

⊕   1 m = 1000 millimeters

⇒   1 km = (1000 × 1000) millimeters

⇒   0.68 km = (0.68 × 1000 × 1000) millimeters

⇒   0.68 km = 680,000 millimeters

Answer: Airplane is 680,000 millimeters long

If an airplane is 0.68 Kilometers long, the length of the airplane in millimeters would be 680000 Millimeters, therefore the correct answer is option D.

A unit of measurement is a specified magnitude of a quantity that is established and used as a standard for measuring other quantities of the same kind.

As given in the problem, If an airplane is 0.68 Kilometers long, then we have to find out the length of the airplane in millimeters,

1 kilometers = 1000 meters

1 meter = 100 centimeters

1 centimeters = 10 millieters

As given the length of the plane is 0.68 Kilometers.

0.68 kilometers = 680 meters

0.68 kilometers = 680×100 centimeters

0.68 kilometers = 680×100×10  millimeters

                           = 680,000 millimeters

Thus, the correct answer is option C.

To learn more about the unit of measurement from here, refer to the link;

brainly.com/question/12629581

#SPJ2

Answer:

the pulley system is very efficient

Explanation:

Given;

load, L  = 250 N

distance moved by the load, a = 4.5 m

distance moved by the effort, e = 2.5 m

let the force or effort applied = F

Apply the principle of conservation of energy;

F x e = L x a

F = (L x a) / e

F = (250 x 4.5) / 2.5

F = 450 N

The efficient of the pulley system;

E = Output force / Input force

E = (450 x 2.5) / (250 x 4.5)

E = 1 = 100%

Therefore, the pulley system is very efficient

Answer:

it is maybe A but i'm not 100% sure

Explanation:

its the only one that is mixed

Answer:

For every action, there is an equal and opposite reaction

Explanation:

Newton's Third Law of Motion states "To every action, there is an equal and opposite reaction; action and reaction forces act on different bodies".

→  Energía cinética

[tex]\large {\boxed {\bf E_c = \cfrac{mv^2}{2} }}[/tex]

[tex]\large {\text {$ \blue {\sf 250 g \rightarrow 0,25 kg }$}}[/tex]

[tex]\large {\text {$ \purple {\sf E_c = \cfrac{ 0,25 \cdot 25 }{2} \rightarrow \quad \cfrac{6,25}{2} = 3,125} $}}[/tex]

[tex]\large {\boxed {\boxed {\boxed {\bf E_c = 3,125 }}}}[/tex]

Option C: Later in the day, less power is developed in lifting each box

Answer:

Later in the day, less power is developed in lifting each box.

power= workdone÷time

Answer:

  τ = 36 10⁻³ s

Explanation:

The charge of a circuit Rc is given by the expression

          q = q₀ (1 - [tex]e^{-t/ \tau }[/tex])

          q / q₀ = 1 - e^{-t/  \tau }

in this exercise they indicate that

          q / q₀ = ½

for a time t = 25 10⁻³ s

we substitute

          ½ = 1 - [tex]e^{- 25 \ 10^{-3} / \tau}[/tex]

          e^{- 25 \ 10^{-3} /  \tau} =  1 -½

         - 25 10⁻³ /τ = ln 0.5

         -25 10⁻³ / ln 0.5 = τ

         τ = 36 10⁻³ s

(a) 3.2 x 10²s

(b) 0.9 m/s (S 13 E)

(c) 2.9 x 10²m

The sketch illustrating the scenario has been attached to this response.

As shown;

The fish swims due east with a velocity [tex]V_{x}[/tex] = 0.2m/s

The river current has a velocity [tex]V_{y}[/tex] due South = 0.9m/s

The resultant of the velocity is V

The width of the river is x = 64m

(a) To calculate how long it took the fish to get across the river, we know that velocity is the rate of change in distance, therefore we can use the relation;

V = [tex]\frac{d}{t}[/tex]      -------------(i)

Where;

V = velocity of the fish = [tex]V_{x}[/tex] = 0.2m/s

d = distance from the start to the end = width of the river = x = 64m

t = time taken to move for that distance

Make t subject of the formula in equation (i);

t = [tex]\frac{d}{V}[/tex]

Substitute the values of d and V into the equation;

t = [tex]\frac{64m}{0.2m/s}[/tex]

t = 320 s

t = 3.20 x 10²s

Therefore, the time taken for the fish to get across the river is 3.20 x 10²s

(b) The resulting vector of the fish is V whose magnitude is the algebraic sum of vectors  [tex]V_{x}[/tex] and  [tex]V_{y}[/tex], and direction is given by θ. i.e

The magnitude of the resulting vector is;

|V| = [tex]\sqrt{(V_x)^2 + (V_y)^2}[/tex]

|V| = [tex]\sqrt{(0.2)^2 + (0.9)^2}[/tex]

|V| = [tex]\sqrt{(0.04) + (0.81)}[/tex]

|V| = [tex]\sqrt{(0.85)}[/tex]

|V| = 0.92m/s

|V| ≅ 0.9m/s

The direction of the resulting vector θ and is given by;

tan θ = [tex]\frac{V_y}{V_x}[/tex]

tan θ = [tex]\frac{0.9}{0.2}[/tex]

tan θ = 4.5

θ = tan⁻¹ ( 4.5)

θ = 77.47° South of East.

θ  ≈ 77.5° South of East.

Subtracting θ = 77.5° from 90° gives its value East of South

i.e

90 - 77.5 = 12.5° East of South

This can also be written as S12.5°E

Approximating to the nearest whole number gives S 13 E

Therefore, the resulting velocity of the fish is 0.9m/s in the direction S13°E

(c) When the fish arrives on the opposite bank, its distance from being at the point directly across from where it started is the product of the velocity of the river current and the time taken by the fish to get across the river. This point is equivalent to k as shown in the diagram.

Therefore;

distance = velocity of river current x time taken

distance = 0.9m/s x 3.20 x 10²s

distance = 2.88 x 10²m

distance ≅ 2.9 x 10²m

Notice that the velocity of the river current is used since that's the velocity of the fish on the y-axis.