at what point does the skater have the least amount of KE kinetic energy?

Answer:

Friction can be minimized by using lubricants like oil and grease and by using ball bearing between machine parts. A substance that is introduced between two surfaces in contact, to reduce friction, is called a lubricant. Fluid friction can be minimized by giving suitable shapes to the objects moving in the fluids.

Explanation:

hope it helps

Answer:

D. The tea loses heat to the spoon causing the spoon to become warmer

Explanation:

When the silver spoon at a lower temperature than the tea, is added to the tea, it makes thermal contact. Hence, the heat transfer starts between the two until the equilibrium is reached. We know that the heat transfer takes place from the body with a higher temperature to a body with a lower temperature. As a result, the body with higher temperature loses heat and its temperature lowers down. While the body with a lower temperature gains heat and its temperature rises.

Therefore, the correct option is:

D. The tea loses heat to the spoon causing the spoon to become warmer

Answer:

La distancia horizontal que recorrerá la caja con medicina antes de caer al río es 583.1 metros.

Explanation:

Una caja con medicina es lanzada desde un avión localizado a una distancia vertical de 340 m por encima de un río.  Este movimiento posee una composición en dos dimensiones: uno horizontal sin aceleración, y el otro vertical con aceleración constante debido a la gravedad.  Por lo que se trata de un movimiento rectilíneo uniforme (MRU) en su trayectoria horizontal o eje horizontal (es decir, su velocidad es constante) y un movimiento uniformemente variado (MRUV) en su trayectoria vertical o en el eje vertical (es decir, su aceleración es constante).

En este caso, son conocidos los datos, considerando el sistema de referencia de la imagen:

En el caso del MRUV, la posición puede calcularse mediante la expresión:

Posición final= Posición inicial + Velocidad inicial*t + [tex]\frac{1}{2}[/tex]*a*t²

donde a es la aceleración y t el tiempo transcurrido.

En este caso, reemplazando los datos conocidos, teniendo en cuenta que el MRUV sucede en la trayectoria vertical y que la aceleración es el valor de la gravedad:

0 m= 340 m + 0 m/s*t + [tex]\frac{1}{2}[/tex]* (-9.8 m/s²)* t²

Resolviendo:

-340 m= [tex]\frac{1}{2}[/tex]* (-9.8 m/s²)* t²

[tex]\frac{-340 m}{\frac{1}{2} *(9.8\frac{m}{s^{2} } )} =t^{2}[/tex]

69.39 s²= t²

t= √69.39 s²

t= 8.33 s

La posición en MRU se obtiene mediante:

Posición final= Posición inicial + velocidad* tiempo

Con los datos conocidos y el tiempo calculado previamente, es posible calcular la distancia horizontal que recorrerá la caja con medicina antes de caer al río, siendo la posición inicial en x igual a cero:

Posición final= 0 m + 70m/s* 8.33 s

Posición final= 583.1 m

La distancia horizontal que recorrerá la caja con medicina antes de caer al río es 583.1 metros.

Veremos que la distancia horizontal que recorre la caja es 583.1 metros.

Recordar que la velocidad vertical y horizontal son independientes.

Aqui, lo primero que debemos hacer es encontrar el tiempo que la caja tarda en llegar al suelo.

Para ello usamos la ecuación de movimiento vertical:

p(t) = (-4.9 m/s^2)*t^2 + v*t + h

Donde el primer termino representa la gravedad, el segundo la velocidad inicial (que es cero en este caso) y el tercero la altura inicial, que es 340m.

p(t) = (-4.9 m/s^2)*t^2 + 340m

La caja llegara al suelo cuando la función de arriba sea igual a cero:

(-4.9 m/s^2)*t^2 + 340m = 0

t = √(340m/(4.9 m/s^2)) = 8.33 s

Es decir, la caja tarda 8.33 segundos en llegar al suelo.

Esto significa que la caja se va a mover horizontalmente durante 8.33 segundos con una velocidad de 70m/s (la que tenía el avion). Es decir, la distancia horizontal que se mueve la caja es :

D = 8.33s*(70m/s) = 583.1 m

Sí quieres aprender más sobre ecuaciones de movimiento, puedes leer:

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Answer:

has more energy, has a greater amplitude, has a higher frequency

Explanation:

Answer:

1. 11 A

2. 240 V

3. 8 Ω

4. 60 C

5. 14400 C

Explanation:

1. Determination of the current.

Voltage (V) = 110 V

Resistance (R) = 10 Ω

Current (I) =?

V = IR

110 = I × 10

Divide both side by 10

I = 110 / 10

I = 11 A

2. Determination of the voltage

Current (I) = 3 A

Resistance (R) = 80 Ω

Voltage (V) =?

V = IR

V = 3 × 80

V = 240 V

3. Determination of the resistance.

Current (I) = 0.5 A

Voltage (V) = 4 V

Resistance (R) =?

V = IR

4 = 0.5 × R

Divide both side by 0.5

R = 4 / 0.5

R = 8 Ω

4. Determination of the charge

Current (I) = 2 A

Time (t) = 30 s

Charge (Q) =?

Q = it

Q = 2 × 30

Q = 60 C

5. Determination of the charge.

We'll begin by converting 20 mins to seconds. This can be obtained as follow:

1 min = 60 s

Therefore,

20 mins = 20 × 60

20 mins = 1200 s

Finally, we shall determine the charge as follow:

Current (I) = 12 A

Time (t) = 1200 s

Charge (Q) =?

Q = it

Q = 12 × 1200

Q = 14400 C

Answer:

D. 75 watts

Explanation:

brainliest please? i've just answered 3 of your questions and they were all correct! :) i hope i helped!

Answer:

(D) =75 WATTS

Explanation:

p(power)=i(current)×v(voltage)

p = 0.625 × 120

p =75 watts

Answer: True

Explanation:

Explanation:

heat but I dont see answer choices

Answer:

In sea-floor spreading, the sea floor spreads apart along both sides of a mid-ocean ridge as new crst is added. As a result, the ocean floors move like conveyor belts, carrying the continents along with them.

Explanation:

Answer:

An object is in notion if its position change with time.

Answer:

A

Explanation:

Answer: 420 km

Explanation:

120 per hour, 3.5 hours

120 x 3.5 = 420

Answer:

They store floodwater

Explanation:

Answer:

On the other hand, power is a scalar quantity and is basically the amount of energy consumed per unit time which has no direction.

Horsepower HP 746 watts

Kilowatts kW 1×103W

Megawatts MW 1×106W

Gigawatts GW 1×109W

The S.I unit of power is Watt(W) which is joule per second.

Answer:

Explanation:

Laminar Flow is a very important topic discussed in physics in the subject of fluid dynamics. Basically, it explains how fluid particles behave at lower velocities. In such cases and when the viscosity of the fluid is low, the fluid particles flow smoothly in perfectly perpendicular layers that do not collide or cross each other. Unlike turbulent flow, which is the opposite. An example of Laminar flow can be seen when you open up a water hose with little pressure, the water simply flows out of the hose and looks very clear and smooth.

Answer:

The force of friction opposes the motion of an object, causing moving objects to lose energy and slow down.

Explanation:

When the balloon is kept in the sun, due to Sun's heat, the kinetic energy of gaseous particles inside the balloons also gets increased and the balloon expands. This will increase the pressure on the walls of the balloon. It continues to expand and comes to a stage when the baloon bursts.

Answer:

what scenario i dont understand

Explanation:

step by step explenation

Answer:

Ok, first is important that you understand how the heat radiation works.

All the objects that have some heat energy in them, radiate some of that energy in the form of electromagnetic waves.

Particularly, the Sun radiates a lot of energy (at the point that if you step under the sunlight, you can feel on your skin the heat that comes from the sun, this is due to radiation).

Now, suppose that you have a thin coat of water over you, then the material that gets impacted by that radiation will be the water and not you, and then the energy is dissipated (some of the energy goes to your body and some go to the air)

This is one way in which spraying water over themselves helps the elephants to keep them cool.

Another way in which heat can be transferred is by conduction.

When you have a hot object and a cool object, and you put them together (so the objects touch each other), the heat will flow from the hotter object to the cooler object until both objects have the same temperature.

Then if the elephant body temperature is larger than the temperature of the water that the elephant sprays over his body, when the water touches the body some of the heat in the elephant body will be transferred to the coat of water, and in this way, the temperature of the elephant's body decreases.

These are the two ways we wanted to find.

Answer:

opaque

Explanation:

Materials such as wood, stone, and metals are opaque to visible light.

Explanation:

light waves because the categorised under mechanical waves

Answer:

A mass driver or electro magnetic catapult is a proposed method of non-rocket space launch which would use a linear motor to accelerate and catapult payloads up to high speeds. All existing and contemplated mass drivers use coils of wire energized by electricity to make electromagnets.

Explanation:

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Answer:

1.5 m/s

Explanation:

The dart moves when it leaves the spring gun with a velocity of 22.4 m/s.

Potential energy is defined as the stored energy that depends on the relative position of different parts of a system such as springs have more potential energy when it will be compressed or stretched.

For velocity calculation of the dart when it leaves the spring gun, using the formula for potential energy stored in a spring:

[tex]PE = (1/2)kx^2[/tex]

where,

k is the spring constant

x is the compression of the spring.

Since the spring is compressed by 5 cm, the potential energy stored in it is:

[tex]PE = (1/2)(250 N/m)(0.05 m)^2[/tex]

PE = 6.25 J

The potential energy stored in the spring will be transferred to the dart when it is released which can be calculated from the velocity of the dart using the equation of conservation of energy:

[tex]PE = (1/2)mv^2[/tex]

where,

m is the mass of the dart

v is its velocity.

Solving for v:

v = sqrt(2PE/m)

=> sqrt(2(6.25 J)/(0.025 kg))

=> 22.4 m/s.

Thus, the dart moves when it leaves the spring gun with a velocity of 22.4 m/s.

Learn more about Velocity, here:

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Answer:

head

four head

hair

eyes

ears

nose

lips

chick

chin

eyebrow

eyelid

Answer:

it would be c, an increase in competition for abiotic factors because if more trees are to be planted, less sunlight would seep through the leaves, leaving the producers to gain the abiotic factors to do with sunlight, temperature, and water

I hope this helps!!

have a wonderful day!

-millie :D

Answer:

6.4 Joules

Explanation:

For springs, Hooke's law states that;

F = ke

where F is a force applied, e is the extension and k is the spring constant.

Work done in a spring is the same as the potential energy stored in the spring. So that;

Work done = [tex]\frac{1}{2}[/tex] k[tex]e^{2}[/tex]

e = [tex]x_{2}[/tex] - [tex]x_{1}[/tex]

[tex]x_{2}[/tex] = 4 cm = 0.4 m

[tex]x_{1}[/tex] = 0

So that,

[tex]x_{2}[/tex] - [tex]x_{1}[/tex] = 0.4 m

Thus,

Work done = [tex]\frac{1}{2}[/tex] x 80 x [tex](0.4)^{2}[/tex]

                   = 40 x 0.16

                   = 6.4

Work done = 6.4 J

The work done by the force on the spring is 6.4 Joules.