How do you put 1/2000 into scientific notation? *

there are two types of waves: electromagnetic and mechanical. can either type travel regardless of the presence of a medium?

Dmitry_Shevchenko [17]

Yes, electromagnetic can travel without medium.

Mechanical waves and electromagnetic waves are two important ways that energy is transported in the world around us.

Waves in water and sound waves in air are two examples of mechanical waves.

Mechanical waves are caused by a disturbance or vibration in matter, whether solid, gas, liquid, or plasma.

Matter that waves are traveling through is called a medium.

These mechanical waves travel through a medium by causing the molecules to bump into each other, like falling dominoes transferring energy from one to the next.

Sound waves cannot travel in the vacuum of space because there is no medium to transmit these mechanical waves.

On the other hand electromagnetic waves don't require medium for its propagation.

An easy example would be light which is an EM wave reaches earth even though space has no medium.

Learn more about different types of waves here:

brainly.com/question/13364787

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3 0

1 year ago

Having difficulty finding the PE and KE for these values no mass is given. Does anyone know to go solve these?

Alexandra [31]

11) $1.04\cdot 10^7 J$

12) $1.04\cdot 10^7 J$

13) 50.0 m/s

14) 41.6 m/s

Explanation:

11)

The potential energy of an object is the energy possessed by the object due to its position relative to the ground. It is given by

$PE=mgh$

where

m is the mass of the object

g is the acceleration due to gravity

h is the height relative to the ground

Here in this problem, when the train is at the top, we have:

m = 8325 kg (mass of the train + riders)

$g=9.8 m/s^2$ (acceleration due to gravity)

h = 127 m (height of the train at the top)

Substituting,

$PE=(8325)(9.8)(127)=1.04\cdot 10^7 J$

12)

According to the law of conservation of energy, the total mechanical energy of the train must be conserved (in absence of friction). So we can write:

$KE_t + PE_t = KE_b + PE_b$

where

$KE_t$ is the kinetic energy at the top

$PE_t$ is the potential energy at the top

$KE_b$ is the kinetic energy at the bottom

$PE_b$ is the potential energy at the bottom

The kinetic energy is the energy due to motion; since the train is at rest at the top, we have

$KE_t=0$

Also, at the bottom the height is zero, so the potential energy is zero

$PE_b=0$

Therefore, we find:

$KE_b=PE_t=1.04\cdot 10^7 J$

13)

The kinetic energy of an object is the energy of the object due to its motion. Mathematically, it is given by

$KE=\frac{1}{2}mv^2$

where

m is the mass of the object

v is the speed of the object

From question 12), we know that the kinetic energy of the train at the bottom is

$KE=1.04\cdot 10^7 J$

We also know that the mass is

m = 8325 kg

Therefore, we can calculate the speed of the train at the bottom:

$v=\sqrt{\frac{2KE}{m}}=\sqrt{\frac{2(1.04\cdot 10^7)}{8325}}=50.0 m/s$

14)

At the top of the second hill, the total mechanical energy of the train is still conserved.

Therefore, we can write again:

$KE_1 + PE_1 = KE_2 + PE_2$

where

$KE_1$ is the kinetic energy at the top of the 1st hill

$PE_1$ is the potential energy at the top of the 1st hill

$KE_2$ is the kinetic energy at the top of the 2nd hill

$PE_2$ is the potential energy at the top of the 2nd hill

From the previous questions, we know that

$KE_1=0$

and

$PE_1=1.04\cdot 10^7 J$

The height of the second hill is

h = 39 m

So we can also find the potential energy at the second hill:

$PE_2=mgh=(8325)(9.8)(39)=3.2\cdot 10^6 J$

So, the kinetic energy at the second hill is

$KE_2=PE_1-PE_2=1.04\cdot 10^7 - 3.2\cdot 10^6 =7.2\cdot 10^6 J$

And so, the speed is

$v=\sqrt{\frac{2KE_2}{m}}=\sqrt{\frac{2(7.2\cdot 10^6)}{8325}}=41.6 m/s$

4 0

3 years ago

A parcel of land is in the shape of an isosceles triangle. The base has a length of 425 ft.; the other sides, which are of equal

kogti [31]

Answer:

The answer to your question is 636.6 ft

Explanation:

Data

base = 425 ft

angle = 39°

See the picture below

1.- Divide the triangle to get two right triangles.

Now the superior angle will measure 19.5° and the opposite side will measure 212.5 ft

2.- Use the trigonometric function sine to find the hypotenuse

sin 19.5 = 212.5/hyp

solve for hyp

hyp = 212.5 / sin 19.5

Result

hyp = 212.5/ 0.333

hyp = 636.6 ft

4 0

3 years ago

An egg rolls off a kitchen counter and breaks as it hits the floor. The counter is 1.0 m high, the mass of the egg is about 50 g

crimeas [40]

Use equations of motion to find the velocity just before it hits the floor:
Vf^2 = Vi^2 + 2gx 
Final velocity = 4.42m/s 

Impulse is change in momentum so: 
m(Vf - Vi) = 0.05(0 - 4.42) 
= - 0.221 kg.m/s

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions here.

3 0

3 years ago

Newton concluded that some force had to act on the moon because

Dimas [21]

Think in gravity, the moon is orbiting the Earth because of gravitational pull/force. Without this gravitational pull, the moon will just move in a straight line (Newton's first law).

6 0

4 years ago