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3 years ago

What would be a good example of kinetic energy?

Physics

1 answer:

Free_Kalibri [48]3 years ago

7 0

Answer:

3) a skier racing down a hill

Explanation:

Remember kinetic energy is energy which a body possess by virtue of being in motion. So anything that is in motion will gain kinetic energy and lose potential energy. Answer 3 was the only object in motion. Kinetic energy is also named energy of motion.

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A bird is flying in a room with a velocity field of . Calculate the temperature change that the bird feels after 9 seconds of fl

Korvikt [17]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The temperature change is $\frac{dT}{dt} = 1.016 ^oC/m$

Explanation:

From the question we are told that

The velocity field with which the bird is flying is $\vec V = (u, v, w)= 0.6x + 0.2t - 1.4 \ m/s$

The temperature of the room is $T(x, y, u) = 400 -0.4y -0.6z-0.2(5 - x)^2 \ ^o C$

The time considered is t = 10 \ seconds

The distance that the bird flew is x = 1 m

Given that the bird is inside the room then the temperature of the room is equal to the temperature of the bird

Generally the change in the bird temperature with time is mathematically represented as

$\frac{dT}{dt} = -0.4 \frac{dy}{dt} -0.6\frac{dz}{dt} -0.2[2 * (5-x)] [-\frac{dx}{dt} ]$

Here the negative sign in $\frac{dx}{dt}$ is because of the negative sign that is attached to x in the equation

$\frac{dT}{dt} = -0.4v_y -0.6v_z -0.2[2 * (5-x)][ -v_x]$

From the given equation of velocity field

$v_x = 0.6x$

$v_y = 0.2t$

$v_z = -1.4$

$\frac{dT}{dt} = -0.4[0.2t] -0.6[-1.4] -0.2[2 * (5-x)][ -[0.6x]]$

substituting the given values of x and t

$\frac{dT}{dt} = -0.4[0.2(10)] -0.6[-1.4] -0.2[2 * (5-1)][ -[0.61]]$

$\frac{dT}{dt} = -0.8 +0.84 + 0.976$

$\frac{dT}{dt} = 1.016 ^oC/m$

5 0

3 years ago

Which is carried by waves?

Alex787 [66]

Answer:

Waves carry energy from one place to another. Because waves carry energy, some waves are used for communication, eg radio and television waves and mobile telephone signals. Some types of waves need to be transmitted through matter, either a solid, liquid or a gas. For example, water waves have to travel in water.

5 0

3 years ago

Read 2 more answers

A satellite is in elliptical orbit with a period of 7.20 104 s about a planet of mass 7.00 1024 kg. At aphelion, at radius 5.1 1

soldi70 [24.7K]

Answer:

1.64x $10^{-4}$ rad/s

Explanation:

Given:

satellite is in elliptical orbit with a period T= 7.20 x $10^{4}$ s

Mass of planet m= 7.00x $10^{24}$ kg

Satellite's angular speed ωa- = 4.987 10-5 rad/s

At aphelion, at radius Ra= 5.1 x 10^7 m

Assuming torque is zero for this system, therefore, the conservation of angular momentum can be defines as

Lp = La

Ip ωp = Ia ωa--->eq(1)

Where,

'a' represents aphelion and 'p' represents perihelion

ω represents angular velocity

and I represents the rotational inertia

Since, I= 1/2 mR²

Here R is the radius at aphelion / perihelion

m = mass of planet

eq(1)=> ωp= Ia ωa/ Ip

ωp= (1/2 m Ra² ωa) / 1/2 m Rp²

ωp= (Ra/Rp)² ωa --->eq(2)

In order to find Rp, we use : 2a= Rp + Ra

where a represents semimajor axis

with the help of Kepler's third law for elliptical orbits

a= ∛(GmT²/4π²)

a= ∛ 6.67x $10^{-11}$ x 7.00x $10^{24}$ x (7.20 x $10^{4}$ )² / 4π²

a= 3.97 x $10^{7}$ m

2a= Rp + Ra

Rp= 2a-Ra

Rp= 2 x 3.97 x $10^{7}$ - 5.1x $10^{7}$

Rp= 2.84 x $10^{7}$ m

Substituting all the required values in eq 2, we have

ωp= (Ra/Rp)² ωa

ωp= (5.1x $10^{7}$ /2.84 x $10^{7}$ )² x 4.987 x $10^{-5$

ωp= 3.224 x 4.987 x $10^{-5$

ωp= 1.64x $10^{-4}$ rad/s

Therefore, angular speed at perihelion is 1.64x $10^{-4}$ rad/s

3 0

3 years ago

Which is the best example of Newton's first law of motion

Svet_ta [14]

Object will remain without motion unless some kind of force forces it to change. Hope this helps

4 0

3 years ago

Read 2 more answers

In a series circuit what effect will adding more resistors to the circuit have

zhuklara [117]

Answer:In a series circuit, adding more resistors increases total resistance and thus lowers current. But the opposite is true in a parallel circuit because adding more resistors in parallel creates more choices and lowers total resistance. If the same battery is connected to the resistors, current will increase.

Explanation:

8 0

3 years ago