Kelly walks 5 km to school. It takes her 1.5 hours. Calculate her speed in m/s

Water has a mass per mole of 18.0 g/mol, and each water mo- lecule (H2O) has 10 electrons. (a) How many electrons are there in o

Dovator [93]

Answer:

a) There are $3,35*10^{26}$ electrons in a liter of water.

b) The net charge is -53601707,1 C

Explanation:

a) To find out how many electrons are in a liter of water (equivalent to 1000 grams of water), we have to find out how many molecules of water there are and then multiply it by 10 (e- per molecule).

We can find out how many molecules are by finding the number of moles and then multiplying it by Avogadro's number (number of elements per mol):

$e^{-}= \frac{m_{water} }{M_{water} } * Avogadro* \frac{e^{-} }{molecule}= \frac{1000g }{18g/mol} * 6,022*10^{23} * \frac{10e^{-} }{molecule}=3,35*10^{26} e^{-}$

b) As all electrons have the same charge, in order to find the net charge of those electrons we have to multiply the charge of a single electron by the number of electrons:

$Net charge= -1,602*10^{-19} \frac{C}{e^{-} } *3,35*10^{26} e^{-}=-53601707,1 C$

An important clarification is that while the net charge may seem huge, water as a whole is a neutral medium, because there are as many protons as there are electrons, and as they have the same charge, the net charge of water is 0.

8 0

4 years ago

A ferris wheel has a radius of 36 feet and completes one revolution every 5.4 minutes. what is the speed of the ferris wheel (in

KIM [24]

In order to find the speed per minute you will have to divide the two numbers together. You need to do 36/5.4 so the answer will be around 6.7 feet per minute.

4 0

3 years ago

A golf ball is whacked in a direction 25 degrees south of the east axis. The ball travels 125m. What are the east and north comp

Natalka [10]

We are given:

Direction of motion: 25 degrees south of the east axis

Distance covered = 125 m

East component of the Ball:

this component is denoted by green color in the image

Once we drop a perpendicular from the end of the direction vector on the x-axis, we get a right angled triangle

The magnitude of the side of the triangle on the x-axis denotes the east component of the ball

Using trigonometry, we find that the east component of the ball is:

125 * Cos(25 degrees)

125 * 0.9 = 112.5 i (here, i denotes rightward direction on the x-axis)

North Component of the Ball:

this component is denoted by blue color in the image

Using trigonometry, we find that the North component of the ball is:

125* Sin(25 degrees) (-j) [j denotes upward movement on the y-axis, since the vector is acting downwards, we have used '-j']

125 * 0.42 (-j)

52.5 (-j) = -52.5 j

Therefore the direction vector of the ball is 112.5 i - 52.5 j

where 112.5 i is the East Component and -52.5 is the North Component

3 0

3 years ago

Find the magnitude of the vector v given its initial and terminal points. Round your answer to four decimal places.

Sliva [168]

Complete Question

The complete question is shown on the first uploaded image

Answer:

The value is $|v| = 6.93$

Explanation:

From the question we are told that

The initial point is $(x_1 , y_1 , z_1 ) = (-1 , 7 , 4 )$

The terminal point is $(x_2 , y_2 , z_2) = (-5 , 11, 8 )$

Generally the magnitude of the vector is mathematically represented as

$|v| = \sqrt{(x_2 -x_1 )^2 + (y_2 - y_1 )^2 + (z_2 -z_1)^2}$

=> $|v| = \sqrt{(-5 -(-1) )^2 + (11 - 7 )^2 + (8 -4)^2}$

=> $|v| = 6.93$

3 0

3 years ago

It requires 350 joules to raise a certain amount of a substance from 10.0°C to 30.0°C. The specific heat of the substance is 1.2

Akimi4 [234]

I'll assume you are looking for the mass of the object, since that is the missing piece of the puzzle.

The important equation for heat and energy is

Energy = mass × specific heat × change in temperature

Things we know:
Energy needed is 350 J.
Specific heat = 1.2 J/g°C
Temp. change = (30-20)°

Now we just need to plug those in and rearrange the formula to find the mass!

350 = mass × 1.2 × 10

6 0

4 years ago

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