W=225 J<br> P=25 W<br> t=?<br> what's T

How many neutrons does element x have if it's atomic number is 27 and it's mass number is 74

Makovka662 [10]

Atomic number=Proton count

Atomic mass=Proton count+ neutron count

Neuton Count=Atomic mass-Proton count

Proton count=Atomic number=27

Mass number=74

Neuton count= 74-27=47

3 0

3 years ago

A cosmic ray (an electron or nucleus moving ar speeds close to the speed of light) travels across the Milky Way at a speed of 0.

Fiesta28 [93]

Answer:

Cosmic ray's frame of reference: 99,875 years

Stationary frame of reference: 501,891 years

Explanation:

First of all, we convert the distance from parsec into metres:

$d=30,000 pc =9.26\cdot 10^{20} m$

The speed of the cosmic ray is

$v=0.98 c$

where

$c=3.0 \cdot 10^8 m/s$ is the speed of light. Substituting,

$v=(0.98)(3.0\cdot 10^8)=2.94\cdot 10^8 m/s$

And so, the time taken to complete the journey in the cosmic's ray frame of reference (called proper time) is:

$T_0 = \frac{d}{v}=\frac{9.26\cdot 10^{20}}{2.94\cdot 10^8}=3.15\cdot 10^{12} s$

Converting into years,

$T_0 = \frac{3.15\cdot 10^{12}}{(365\cdot 24\cdot 60 \cdot 60}=99,875 years$

Instead, the time elapsed in the stationary frame of reference is given by Lorentz transformation:

$T=\frac{T_0}{\sqrt{1-(\frac{v}{c^2})^2}}$

And substituting v = 0.98c, we find:

$T=\frac{99,875}{\sqrt{1-(\frac{0.98c}{c})^2}}=501,891 years$

3 0

3 years ago

A 10.0-kg animal is running at a rate of 3.0 m/s. What is the kinetic energy of the animal?

Ilya [14]

Kinetic energy is calculated by using formula:

Ek = 1/2*m*v^2

Now we replace values of mass and speed in this formula.

Ek = 1/2*10*3^2 = 45.0J

When you have a formula and all variable values are given in the text of question just replace variable values in equation and find the final value.

4 0

3 years ago

With what magnitude of force does a ball of mass 0.75 kilograms need to be hit so that it accelerates at the rate of 25 meters/s

SSSSS [86.1K]

Answer:

Assume that the ball undergoes motion along a straight line. ... F = m A Force = (mass) x (acceleration) The question tells you the mass and the acceleration. All YOU have to do is take the numbers and pluggum into Newton's 2nd law. F = m A = (0.75 kg) (25 m/s²) = (0.75 x 25) kg-m/s² = 18.75 Newtons .

Explanation:

i looked it up ok

8 0

3 years ago

Read 2 more answers

All of the alkali metals, Group 1, have one valence electron. Which of these would represent the oxidation number of the alkali

melamori03 [73]

The elements found in the Group 1, or the Alkali Metal Group, have electronic configurations that end in $s^{1}$ .This means that they have 1 electron readily available to release in order to achieve a stable state.

When these atoms release the valence electron, they will achieve a stable state. For example, Lithium's stable state will be $Li^{+}$ and Sodium will be $Na^{+}$ .

The oxidation state will then be +1.

The answer is C.

8 0

3 years ago

Read 2 more answers

W=225 J P=25 W t=? what's T