Francium-233 has a half-life of 22 minutes.A Geigor counter gives a reading of 58 counts per minute (cpm) from a sample of francium-233.What will the reading be 22 minutes later?You can ignore background radiation

Acceleration =change in velocity÷Time taken

or, Acceleration =final velocity-Initial velocity÷Time taken

or, a=v-u÷t

or, at=v-u

or, v-u=at

therefore, v=u+at

Answer:

f = 10 Hz

Explanation:

We need to find the frequency of a wave if 10 waves go past in 1 second. Total number of waves per unit time is called frequency. So,

[tex]f=\dfrac{10}{1}=10\ Hz[/tex]

So, the frequency of a wave is 10 Hz.

Answer:

newton(N)

Explanation:

Answer:

when the radius is halved, F becomes 4 times

Explanation:

The formula is given by

[tex]F = \frac{Gm1m2}{r^2}[/tex]

When r is halved:

[tex]F = \frac{Gm1m2}{(1/2r)^2}[/tex]

=> [tex]F = \frac{Gm1m2}{1/4 r^2}[/tex]

=> [tex]F = 4(\frac{Gm1m2}{r^2} )[/tex]

This means when the radius is halved, F becomes 4 times

Answer:

a. 38400j

Explanation:

p= mgh

2400×10×1.6

Answer:

300°

Explanation:

both the angles of incidence and reflection are the same

Answer:

Mass = 386 kg

Explanation:

Density = Mass / Volume

Mass = Density × Volume

Where D = 19300 kg/m³ , V = 0.02 m³

Putting the given in the above formula

Mass = 19300 × 0.02

Mass = 386 kg

Answer:

386 kg

Explanation:

mass = density * volume

= 19300 * 0.02

= 386 kg

Hope this helps!

Answer:

Сила тока 0.994 А

Explanation:

Параметры приведены ниже;

Время = 4 часа = 14 400 с

Масса выпущенного серебра = 16 г

Электрохимический эквивалент серебра = 1,118 мг / с

Формула для количества электричества Q дается следующим образом;

Q = I × t

Куда;

I = ток (A)

t = время в секундах, с

Масса m, образующаяся при электролизе, определяется соотношением;

[tex]m = E_c \times Q = E_c \times I \times t[/tex]

Куда;

[tex]E_c[/tex] = Электрохимический эквивалент серебра = 1,118 мг / с

м = 16 г

Подставляя значения, мы имеем;

Который дает;

[tex]I = \dfrac{16}{1.118 \times 10^{-3} \times 14,400} = 0.994 \, A[/tex]

Следовательно, сила тока = 0,994 А.

Answer:

E=72000J or 72kj

Explanation:

The formula is E=pt you need to convert your t from minutes to seconds before proceeding

Answer:

Speed is a scalar quantity, that is, it is a number and indicates how fast (or slow) one travels at any given time.

Velocity is a vector quantity, this means that it has magnitude and direction, that is, how fast an object travels and its where its going (speed + the direction in which the object moves).

Acceleration is the ratio of the velocity change over the time interval in which this velocity change occurred. Acceleration as well as velocity is a vector quantity so it is made up of magnitude and direction.

The differences between these three quantities are important for the description of the movement. In the case of speed and velocity, its difference lies in the fact that velocity indicates the direction in which the movement is taking place (and speed is only a number), which in many physical phenomena the direction of movement is an important property. And the difference between acceleration and velocity is that acceleration instead of a velocity indicates a change in velocity (either in magnitude, direction or both), which tells us how fast a velocity will increase or decrease over time.

Answer:

B. Neutron has no charge

Answer:

B. Neutron

Explanation:

Firstly, the nucleus is what contains the protons and electrons, so it is not an atomic particle. The electron has a negative charge, and the proton has a positive charge (you can remember this by looking at its prefix 'pro'). This means the neutron has no charge (think of it as neutral).

Answer:

Work done by the force = 1/2m×(v2 - v1)²

m = mass

v2 = final velocity

v1 = initial velocity

= 1/2(0.25)(7.5-5)²

= 1/2(0.25)(2.5)²

= 1/2(0.25)(6.25)

= 0.78J

Hope this helps.

Answer:

194 kg m²

Explanation:

Use parallel axis theorem:

I = I₀ + mr²

I = 25 kg m² + (1 kg) ((5 m)² + (12 m)²)

I = 25 kg m² + 169 kg m²

I = 194 kg m²

Answer:

The new force is 16 times of the initial force.

Explanation:

The electric force between charges is given by :

[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]

If the distance is halved, d' =d/2 and charges are doubles, [tex]q_1'=2q_1\ \text{and}\ q_2'=2q_2[/tex]

New force becomes,

[tex]F'=\dfrac{kq_1'q_2'}{r'^2}\\\\F'=\dfrac{k(2q_1)(2q_2)}{(d/2)^2}\\\\F'=16\times \dfrac{kq_1q_2}{r^2}\\\\F'=16F[/tex]

So, the new force is 16 times of the initial force.

If the distance is halved and the charges of both particles are doubled, the force is 16 times as great.

According to Coulomb's law, the electrostatic force between two charges is given by;

[tex]F=k\frac{q_1 q_2}{r^2}[/tex]

Where 'k' is the Coulomb's constant.

If the charges of both particles are doubled and the distance is halved, the new force will be;

[tex]F\,'=k\frac{2q_1 \times 2q_2}{(r/2)^2}=k \frac{4\times 4\times q_1 q_2}{r^2} =16\,F[/tex]

So, the new force will be 16 times greater than the old force.

Learn more about Coulomb's law here:

https://brainly.com/question/14049417

Answer:

F = m*(g - a) →

a = g - F/m = 0.891 m/s² downward

Explanation:

If elevator was stationary, the normal force of elevator floor on man* would be = mg

mg = (38.5)(9.81) ≈ 378 N.

If elevator is accelerating downward the floor is accelerating away from man and so the normal force will be less than man's weight by: 378 - 343 = 35 N.

Hope this helps.

Answer:

-0.891

Explanation:

negative because downward

Answer:

The frequency of an ocean wave is 15 Hz.  

Explanation:

We are given with, the speed of an ocean wave is 45 m/s. Its wavelength is 3 m

It is required to find the frequency of an ocean wave.

The speed of a wave is given in terms of frequency and wavelength as :

[tex]v=f\lambda[/tex],

f = frequency of ocean wave

[tex]f=\dfrac{v}{\lambda}\\\\f=\dfrac{45}{3}\\\\f=15\ Hz[/tex]

So, the frequency of an ocean wave is 15 Hz.

Explanation:

lighting converts heat energy.

hope you like this .

Answer:

7572 m/s

Explanation:

The force between two masses separated by a distance r is given as:

[tex]F=G\frac{m_1m_2}{r^2}[/tex]

Where F is the attractive force between 2 masses, m1 and m2, r is the distance between the centres of the masses and G is the universal gravitation constant, which is [tex]6.674*10^-11 Nm^2/kg^2[/tex]

The mass of the earth ([tex]m_1[/tex]) is far greater than the mass of the sputnik ([tex]m_2[/tex]). Therefore [tex]m_1m_2=m_1[/tex]. The mass of the sputnik is neglected, therefore:

[tex]F=G\frac{m_1}{r^2}=\frac{(6.674*10^{-11})(5.98*10^{24})}{(6.96*10^6)^2} = 8.2389N[/tex]

But F is actually centripetal acceleration, a = v²/r

[tex]8.2389 = v^2 / 6.96*10^6\\v=7572m/s[/tex]

Answer:

The forces acting on the pen which is still on the table can have two forces acting on them.  The forces are gravitational force and the equal and opposite force to the gravitational forces.

The equal and opposite forces that is applied on the pen keeps the pen still on the table.

So, the statement that no force is applied on the pen which is kept still on the table is wrong as two forces are applied on the pen.

As both the forces are equal and opposite so it is cancelled and is still.

Answer:

[tex] \gamma \: dynamo \: converts \: the \: mechanical \: energy \: into \: electrical \: energy \: .[/tex]

Explanation:

Hope it helps you :)))

Answer:

.

Explanation:

Answer:

[tex]F=F_{f}=1171.5 N[/tex]

Explanation:

We know that the sailboat has a uniform movement, therefore the total force, the engine, and the wind must be equal to the friction force.

[tex]F=F_{f}[/tex]

[tex]F=F_{f}=\sqrt{F^{2}_{engine}+F^{2}_{wind}}[/tex]

[tex]F=F_{f}=\sqrt{900^{2}+750^{2}}[/tex]

[tex]F=F_{f}=1171.5 N[/tex]

Therefore the friction force is 1171.5 N.

I hope it helps you!

Answer:

73 neutrons.

Explanation:

Data obtained from the question:

Mass number of Xenon = 127.

Neutron number =...?

We can obtain the number of neutron present as follow:

Atomic number of Xenon = 54

Recall:

Atomic number = proton number = 54

Mass number = proton + neutron

127 = 54 + Neutron

Neutron = 127 – 54

Neutron = 73.

Therefore, 73 neutrons are present in the Xenon atom.

Answer:

90 m/s

8100 m

Explanation:

Given:

v₀ = 0 m/s

a = 0.5 m/s²

t = 3 min = 180 s

Find: v and Δx

v = at + v₀

v = (0.5 m/s²) (180 s) + 0 m/s

v = 90 m/s

Δx = v₀ t + ½ at²

Δx = (0 m/s) (180 s) + ½ (0.5 m/s²) (180 s)²

Δx = 8100 m

Answer:

858.7 N

Explanation:

The magnetic force on the charge F = Bqv where B = magnetic field strength = 4.02 mT = 4.02 × 10⁻³ T, q = charge = 7.12 μC = 7.12 × 10⁻⁶ C and v = c = speed of light = 3 × 10⁸ m/s

F = Bqc

=  4.02 × 10⁻³ T × 7.12 × 10⁻⁶ C × 3 × 10⁸ m/s

= 858.7 N

Answer:

2 meter per second

Explanation:

kinetic energy = 1/2 m v^2

20J = 1/2 × 10 × v^2

v^2 = 4

v= 2 m/s

Answer:

W=F×H,Power=W/Time

Explanation:

W=Force ×Height

750N×16 =12000

Power=Work/Time

12000/5=2400J

If a car travels 20 miles in 1 hour and 15 minutes, then the average speed of the car would be 7.15 meters/second.

The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object.

As given in the problem, if a car travels 20 miles in 1 hour and 15 minutes, then we have to find the average speed of the car,

1 mile = 1609 meters

20 miles = 20*1609 meters

              = 32180 meters

1 hour = 3600 seconds

1 minutes = 60 seconds

15 minutes = 15*60

                  =900 seconds

1 hour and 15 minutes = 4500 seconds

The average speed of the car = The distance traveled by car/time

                                                  = 32180 meters / 4500 seconds

                                                  = 7.15 meters / seconds

Thus, the average speed of the car would be  7.15 meters/second.

To learn more about speed from here, refer to the link;

brainly.com/question/7359669

#SPJ2

Answer:

What are your thoughts about the connection between exercise and memory?

I think its important to memorize how much u work out and exersize. make sure u dont do it too much or u might pass out. keep track of ur health by memorizing what u ate and when u ate before doing a lot of movement. you might throw up. Exercising is obviously very important for your body.

How often do you exercise?

5 times a week. (5/7 days)

Do you exercise more or less now that you are no longer on campus? Is that a good or bad thing?

A little less. But i think its a good thing

Why?

I used to go to a gym near campus! But now some are a little farther but during this time of quarantine, i work out at home and do the basics like running and agility. I think its good because it teaches me the exercising i can do at home instead of getting memberships and using my money. now i can spend money wisely and still exersize.

Mark as brainliest!

hope this helps! :)

make any changes if ud like

Explanation: