All categories

3 years ago

I have no idea so i'm screwed please help me

Physics

1 answer:

podryga [215]3 years ago

8 0

Answer:

Let N0 be the initial atoms of Be11

N0 / 2^1 = N0 / 2 Number of Be11 after 1 half-life

N0 / 2^2 = N0/ 4 Number of Be11 after 2 half-lives

30/13.81 = 2.17 half lives

N0 / 2^2.17 = N0 / 4.51 = .222 N0 or 22.2 % of atoms remain

You might be interested in

The amount of friction divided by the weight of an object forms a unit less number called the

Romashka [77]

Answer:

Coefficient of friction.

Explanation:

The amount of friction divided by the weight of an object is equal to the coefficient of friction. It is a dimensional less number. It can be given by :

$F=\mu N$

N is normal force.

$\mu$ = coefficient of friction

$\mu=\dfrac{F}{N}$

3 0

3 years ago

The space shuttle is accelerated off its launch pad to a velocity of 525 m/s in 18.0 seconds.

Eva8 [605]

Answer: 29.17m/s^2

Explanation:

Given the following :

Velocity = 525 m/s

Time = 18 seconds

Acceleration = change in Velocity with time

Using the motion equation:

v = u + at

Where v = final Velocity

u = Initial Velocity and t = time

Plugging our values

525 = 0 + a × 18

525 = 18(a)

a = 525 / 18

a = 29.166666

a = 29.17 m/s^2

8 0

3 years ago

Match the definition with the correct term: resistance to flow.

alukav5142 [94]

(1) friction is the force resisting the relative motion of solid surfaces , fluid layers and material elements sliding against each other.
(2) gravity is a science fiction .
(3) Resistance ::: is a property of a conductor by which the passage of current is opposed causing electric energy to be transformed into heat .
(4) viscosity is the quantity that describes a fluid.
(5)

3 0

3 years ago

Which of the following is not a physical change?

Alekssandra [29.7K]

C because of galvination is sized

5 0

3 years ago

What is the maximum wavelength a photon can have if it is to possess sufficient energy to cause this dissociation?

Alona [7]

I attached the full question.
We need to calculate the enthalpy change first:
$\Delta H=$(247kJ)-(142.3kJ)=+105.2kJ$
Keep in mind this is the energy per mole, we need energy per atom:
$E=\frac{105200}{6.02 \cdot 10^{23}}$
We can see that this reaction needs the energy to get started (enthalpy change is positive).
The energy of a photon is given with this formula:
$E=\frac{hc}{\lambda}$
We need this photon to have the same energy (or higher) as our enthalpy change:
$105.2=\frac{6.62\cdot 10^{-34}\cdot 3\cdot 10^ 8}{\lambda}\\ \lambda=\frac{6.62\cdot 10^{-34}\cdot 3\cdot 10^ 8}{105.2/(6.02\cdot 10^{23})} \\\lambda=1.138\mu m$
This wavelenght is clasified as near infrared.

5 0

3 years ago