All categories

3 years ago

Twenty is the _________________ of potassium

Physics

1 answer:

Mumz [18]3 years ago

7 0

Twenty is the atomic number of potassium.

You might be interested in

An excited hydrogen atom releases an electromagnetic wave to return to its normal state. You use your futuristic dual electric/m

Norma-Jean [14]

Answer:

Explanation:

Direction of velocity of electromagnetic wave is given by the formula

E = E j ( vector form )

B = - Bi ( vector form )

Direction of velocity = direction of vector E X B

= E X B

= E j x -Bi

= - EB -k

v = EBk

So the direction of velocity will be along z direction.

6 0

3 years ago

In a World Cup soccer match, Juan is running due north toward the goal with a speed of 7.60 m/s relative to the ground. A teamma

spayn [35]

Answer:

Part a)

$v_{bj} = 11.03 m/s$

Part b)

$\theta = 4.57 degree$ East of South

Explanation:

Part a)

Velocity of Juan is given as

$v_1 = 7.60 m/s \hat j$

velocity of the ball is given as

$v_2 = 12.9(cos31.4 \hat i + sin31.4\hat j)$

now we have

$v_2 = 11\hat i + 6.72\hat j$

Part a)

We need to find velocity of ball with respect to Juan

so it is given as

$v_{bJ} = \vec v_b - \vec v_j$

$v_{bj} = 11\hat i + 6.72 \hat j - 7.6\hat j$

$v_{bj} = 11\hat i - 0.88\hat j$

magnitude of the speed is given as

$v_{bj} = \sqrt{11^2 + 0.88^2}$

$v_{bj} = 11.03 m/s$

Part b)

direction of velocity of the ball

$tan\theta = \frac{v_y}{v_x}$

$tan\theta = \frac{-0.88}{11}$

$\theta = 4.57 degree$ East of South

3 0

2 years ago

18°C = _____ <br> A -255 K<br> B- 0 K<br> C- 18 K<br> D- 291 K

mariarad [96]

Answer:

291 K is the answer

Explanation:

to get Kelvin from Celsius use the following

Kelvin = Celsius +273

= 18 +273

= 291

7 0

2 years ago

In your own words, describe why melting ice with salt freezes cream. Compare your descriptions to your classmates and describe h

gizmo_the_mogwai [7]

Answer:

Water normally freezes at 0°C (32°F). Salt lowers the freezing temperature. (That is, it can remain a liquid at much lower temperatures.)

When sprinkled on ice, the salt lowers the freezing temperature of the water which effectively melts the ice when the salt dissolves into it. There is a limit to how low it can reduce the temperature, though. If the temperature drops below -9°C (15°F), it's too cold for the salt to dissolve into the ice.

When making ice cream, the salt lowers the temperature of the ice and water sufficiently enough to freeze the cream.

3 0

2 years ago

If a wave is traveling at 60cm/second and has a wavelength of 15 cm what is the frequency?

REY [17]

The frequency of the wave is 4 Hz

4 0

2 years ago