Which of the following elements tend to be radioactiv
Check all that apply.
A. Ne
B. Am
C. U
D. K

Answer:

a)   P' = P_original, b)  P ’= P_original + ρ  g Δh

Explanation:

The expression for nanometric pressure is

          P = ρ g h

where ρ  is the density of the liquid and h is the height

a) we change the radius of the barrel, but keeping the same height

as the pressure does not depend on the radius it remains the same

        P' = P_original

b) We change the barrel height

         h ’≠ h

we substitute in the equation

      P ’= ρ  g h’

      h ’= h + Δh

      P ’= ρ  g (h + Δh)

      P ’= (ρ  g h) + ρ  g Δh

      P ’= P_original + ΔP

In this case, the pressure changes due to the new height,

*if it is higher than the initial one, the pressure increases

*if the height is less than the initial one, the pressure is less

Answer:

The value is  [tex]h = 32.91 \ m[/tex]

Explanation:

From the question we are told that

    The diameter of each wheel is  [tex]d = 52 \ cm = 0.52 \ m[/tex]

    The mass of the motorcycle is  [tex]m = 320 \ kg[/tex]

    The rotational kinetic inertia is  [tex]I = 2.1 \ kg \ m^2[/tex]

    The  mass of the  rider is  [tex]m_r = 75 \ kg[/tex]

     The  velocity is  [tex]v = 85 \ km/hr = 23.61 \ m/s[/tex]

      Generally the radius of the wheel is mathematically represented as

      [tex]r = \frac{d}{2}[/tex]

=>     [tex]r = \frac{0.52}{2}[/tex]

=>    [tex]r = 0.26 \ m[/tex]

Generally from the law of energy conservation

     Potential energy  attained  by  system(motorcycle and rider )  =  Kinetic  energy of the system  +  rotational kinetic energy of  both wheels of the motorcycle

=>  [tex]Mgh = \frac{1}{2} Mv^2 + \frac{1}{2} Iw^2 + \frac{1}{2} Iw^2[/tex]

=>    [tex]Mgh = \frac{1}{2} * Mv^2 + Iw^2[/tex]

Here  [tex]w[/tex] is the angular velocity which is mathematically represented as

     [tex]w = \frac{v }{r }[/tex]

So

    [tex]Mgh = \frac{1}{2} * Mv^2 + I \frac{v}{r} ^2[/tex]

Here [tex]M = m_r + m[/tex]

         [tex]M = 320 + 75[/tex]

          [tex]M = 395 \ kg[/tex]

[tex]395 * 9.8 * h = 0.5 * 395 * (23.61)^2 + 2.1 *[\frac{ 23.61}{ 0.26} ] ^2[/tex]

=>   [tex]h = 32.91 \ m[/tex]

Answer:

The mass of the rule is 56.41 g  

Explanation:

Given;

mass of the object suspended at zero mark, m₁ = 200 g

pivot of the uniform meter rule = 22 cm

Total length of meter rule = 100 cm

0                          22cm                                  100cm

-------------------------Δ------------------------------------

↓                                                                       ↓

200g                                                                 m₂  

Apply principle of moment

(200 g)(22 cm - 0)     = m₂(100 cm - 22 cm)

(200 g)(22 cm) = m₂(78 cm)

m₂ =  (200 g)(22 cm)  / (78 cm)

m₂ = 56.41 g  

Therefore,  the mass of the rule is 56.41 g                                            

Explanation:

average speed = total distance travelled / total time travelled

time to travel the first 6km: 6 / 50 = 3/25 (h)

time to travel the next 6km: 6 / 90 = 1/15 (h)

[I think there's problem in the question 'cause 900km/h sounds impossible for normal person to travel in normal condition]

The total time: 3/25 + 1/15 = 14/75 (h)

Average speed over the 12 km drive will be:

[tex] \frac{12}{ \frac{14}{75} } = \frac{450}{7} = 64.3 \: km{h}^{ - 1} [/tex]

Complete question :

A 12 m x 15 m house is built on a 12-cm-thick concrete slab.

What is the heat-loss rate through the slab if the ground temperature is 5°C while the interior of the house is 25°C

Answer:

3kW

Explanation:

Given the following :

Dimension of house :

Length = 12m

Width = 15m

Thickness of concrete slab (t) = 12cm

t in metres :

100cm = 1m

12cm = (12/100)m

= 0.12m

Ground temperature (Tg) = 5°C

Interior temperature = (Th) = 25°C

Thermal conductivity of concrete (K) is approximately 1 Wm/k

Using the relation:

Q = KA * [ (Th - Tg) / d]

A = Length * width = (12 *15) = 180

Q = (1 * 180) * [(25°C - 5°C) / 0.12]

Q = 180 * (20/0.12)

Q = 180 * 16.6666

Q = 3,000W = 3kW

The heat-loss rate is 3kW

Given that,

Dimension of house :

Length = 12m

Width = 15m

Thickness of concrete slab (t) = 12cm

We know that

100cm = 1m

so,

12cm = (12/100)m

= 0.12m

And,

Ground temperature (Tg) = 5°C

Interior temperature = (Th) = 25°C

Q = KA * [ (Th - Tg) / d]

A = Length * width = (12 *15) = 180

Q = (1 * 180) * [(25°C - 5°C) / 0.12]

Q = 180 * (20/0.12)

Q = 180 * 16.6666

Q = 3,000W

= 3kW

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Answer:

The force is  [tex]F = 21.48 \ N[/tex]

Explanation:

From the question we are told that

   The diameter of the wire is  [tex]d = 1.5 \ mm = 1.5 *10^{-3} \ m[/tex]

     The  pressure is  [tex]P = 120 \ a.t.m = 120 * 101.3 *10^{3} = 12156000 Pa[/tex]

Generally the radius of the of the wire is  

     [tex]r = \frac{d}{2}[/tex]

=>    [tex]r = \frac{ 1.5 *10^{-3}}{2}[/tex]  

=>    [tex]r = 7.5 *10^{-4} \ m[/tex]

The Area is evaluated as

     [tex]A = \pi r^2[/tex]

=>    [tex]A = 3.142 * 7.5 *10^{-4}[/tex]

=>    [tex]A = 1.7673*10^{-6} \ m^2[/tex]

Generally pressure is mathematically represented as

     [tex]P = \frac{F}{A }[/tex]

=>   [tex]F = P* A[/tex]

=>    [tex]F = 12156000 * 1.767*10^{-6}[/tex]

=>    [tex]F = 21.48 \ N[/tex]

Answer:

The distance is  [tex]s= 30.3 \ m[/tex]

Explanation:

From the question we are told that

   The  coefficient of static friction is  [tex]\mu_s = 0.42[/tex]

    The  initial speed of the train is  [tex]u = 57 \ km /hr = 15.8 \ m/s[/tex]

For the crate not to slide the friction force must be equal to the force acting on the train i.e

       [tex]-F_f = F[/tex]

The negative sign shows that the two forces are acting in opposite direction

=>   [tex]mg * \mu_s = ma[/tex]

=>   [tex]-g * \mu_s = a[/tex]

=>   [tex]a = -9.8 * 0.420[/tex]

=>   [tex]a = -4.116 m/s^2[/tex]

From equation of motion

  [tex]v^2 = u^2 + 2as[/tex]

Here  v =  0 m/s since it came to a stop

=>   [tex]s= \frac{v^2 - u^2 }{ 2 a}[/tex]

 =>   [tex]s= \frac{0 -(15.8)^2 }{ - 2 * 4.116}[/tex]

=>     [tex]s= 30.3 \ m[/tex]

Explanation:

e(t) = 9t² − 6t + 3

The velocity is the first derivative:

e'(t) = 18t − 6

The acceleration is the second derivative:

e"(t) = 18

Answer:

its an interaction that can move an object; push or pull makes it or gravity, magnetism

Explanation:

its all in the answer

Answer:

In physics, a force is any interaction that, when unopposed, will change the motion of an object. A force can cause an object withmass to change its velocity (which includes to begin moving from a state of rest), i.e., toaccelerate. 

Answer:

0.182C

Explanation:

Using Q= It

= 13x10^3 . 14x10^-6

= 0.182C

Explanation:

We need to solve [tex](5.87\times 10^7)(4.2\times 10^{11})[/tex]

Firstly, multiplying 5.87 and 4.2 = 24.654

Now taking exponent of 10.

We know that : [tex]x^a{\cdot} x^b=x^{a+b}[/tex]

It means, [tex]10^7{\cdot} 10^{11}=10^{11+7}=10^{18}[/tex]

So,

[tex](5.87\times 10^7)(4.2\times 10^{11})=24.654\times 10^{18}[/tex]

In scientific notation,

[tex](5.87\times 10^7)(4.2\times 10^{11})=2.4654\times 10^{19}[/tex]

Hence, the value of [tex](5.87\times 10^7)(4.2\times 10^{11})[/tex] is [tex]2.4654\times 10^{19}[/tex]

Answer:

Explanation:

We need to solve

Firstly, multiplying 5.87 and 4.2 = 24.654

Now taking exponent of 10.

We know that :

It means,

So,

In scientific notation,

Hence, the value of  is

Answer:

Explanation:

The volume rate of flow = a x v where a is cross sectional area of pipe and v is velocity of flow

putting the values

π x .2945² x 12.1

= 3.3  m³ /s

To know the pipe's diameter at the refinery we shall apply the following formula

a₁ v₁ = a₂ v₂

a₁ v₁ and  a₂ v₂ are volume rate of flow of liquid which will be constant .

3.3 = a₂ x 6.29

a₂ = .5246 m³

π x r² = .5246

r = .4087 m

= 40.87 cm

diameter

= 81.74 cm

Answer:

The  correct option is  H

Explanation:

From the question we are told that

    The index of refraction of  coating is  [tex]n_1[/tex]

       The  index of refraction of material  is  [tex]n_2[/tex]

Generally the condition for constructive for a thin film interference is mathematically represented

            [tex]2 * t = [ m + \frac{1}{2}] \frac{\lambda}{n_1 }[/tex]

Here  t represents the thickness

For minimum thickness  m =  0

So

           [tex]2 * t =0 + \frac{1}{2}\frac{\lambda}{n_1 }[/tex]

=>        [tex]t =\frac{\lambda}{4n_1 }[/tex]

Answer:

A

Explanation:

Answer:

A

Explanation:

No evaporation or precipitation in the water cycle occurs over the ocean.

Answer:

6

Explanation:

Given that

dsinθ = mλ,

now, if sinθ = 1, then

m = d / λ, where

m = order of interference

d = distance between the slits

λ = wavelength of light

this is the formula we would use to solve the question

d = 1 / 320 lines/mm

d = 1 / 320*10^3

d = 3.125*10^-6 m

At λ = 551 nm, we have

m = 3.125*10^-6 / 551*10^-9

m = 5.67

5.67 ~ 6

thus, we can say that the orders of visible wavelength 551 nm, can produce is 6

Answer:

No, life would not be to develop

Explanation:

Stars less massive than about 2 solar masses can only produce natural element up to carbon and oxygen, which are the basic elements for building life. However, other more massive elements are needed by life to thrive and function properly, more massive elements like phosphorus, iron necessary for oxygen circulation, calcium for a strong support system, and silicon are essential for for life to form and be sustained here on Earth.

Answer:

The type of medium affects a sound wave as sound travels with the help of the vibration in particles.

Explanation:

As different mediums have different amount and size of particles, for example, the speed of sound is faster through solid than liquid as solids have closely packed particles whereas liquids are loosely packed.

The speed of sound in a given medium is determined by its density and stiffness (or compressibility in the case of gases).The speed of sound increases with the rigidity (or lack of compressibility) of the medium. The speed of sound decreases with increasing medium density.

Any material or area through which a wave is transmitted is referred to as a medium. Four variables impact a wave's speed: wavelength, frequency, medium, and temperature. The wavelength and frequency are multiplied to determine the wave speed (speed = l × f).

Therefore, The rate at which energy is transferred through a medium depends on the amplitude of the vibrations of its constituent particles; the higher this rate, the more powerful the sound wave.

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Answer:

(I). The sum of the vectors is (7i-5j).

(II). The sum of the vectors is (8i+7j).

Explanation:

Given that,

(I). Vector A [tex]A=3i-12j[/tex]

Vector B [tex]B=4i+7j[/tex]

Suppose, (II). Vector A [tex]A=6i+15j[/tex]

Vector B [tex]B=2i-8j[/tex]

(I). We need to calculate the sum of the vectors

Using formula of sum

[tex]\vec{C}=\vec{A}+\vec{B}[/tex]

Where,

[tex]\vec{A}= vector A[/tex]

[tex]\vec{B}= vector B[/tex]

[tex]\vec{C}= sum of the vector A and b

Put the value into the formula

[tex]\vec{C}=(3i-12j)+(4i+7j)[/tex]

[tex]\vec{C}=7i-5j[/tex]

(II). We need to calculate the sum of the vectors

Using formula of sum

[tex]\vec{C}=\vec{A}+\vec{B}[/tex]

Put the value into the formula

[tex]\vec{C}=(6i+15j)+(2i-8j)[/tex]

[tex]\vec{C}=8i+7j[/tex]

Hence, The sum of the vectors is (7i-5j).

The sum of the vectors is (8i+7j).

Explanation:

It is given that,

Momentum in y direction is [tex]2.4\times 10^4\ kg-m/s[/tex]

Momentum in x direction is [tex]7\times 10^4\ kg-m/s[/tex]

We need to find the angle of the motion of the two vehicles, with respect to the x-axis. The angle between two vectors is given by :

[tex]\tan\theta=\dfrac{p_y}{p_x}\\\\\tan\theta=\dfrac{2.4\times 10^4}{7\times 10^{4}}\\\\\theta=\tan^{-1}\left(0.342\right)\\\\\theta=18.88^{\circ}[/tex]

So, the angle of the motion of the two vehicles is 18.88 degrees.

Answer:

The parachuter is falling at a speed of 31.667 meters per second.

Explanation:

Given that parachuter falls at constant speed and travelled distance and time are known, the unknown is speed, measured in meters per second, which is obtained by the following kinematic expression:

[tex]s = \frac{d}{t}[/tex]

Where:

[tex]d[/tex] - Travelled distance, measured in meters.

[tex]t[/tex] - Time, measured in seconds.

If [tex]d = 456\,m[/tex] and [tex]t = 14.4\,s[/tex], the speed of the parachuter is:

[tex]s = \frac{456\,m}{14.4\,s}[/tex]

[tex]s = 31.667\,\frac{m}{s}[/tex]

The parachuter is falling at a speed of 31.667 meters per second.

Answer:

[tex] \boxed{\sf Shortest \ possible \ time = 7 \ seconds} [/tex]

Given:

Distance travelled (s) = 8.4 cm

velocity (v) = 1.2 cm/s

To Find:

Shortest possible time (t) in which a bacterium travel a distance 8.4 cm across a Petri Dish

Explanation:

[tex] \boxed{ \bold{\sf Time \ (t) = \frac{Distance \ travelled \ (s)}{Velocity \ (v)}}}[/tex]

Substituting values of Distance travelled (s) & Velocity (v) in the equation:

[tex] \sf \implies t = \frac{8.4}{1.2} [/tex]

[tex] \sf \implies t = \frac{7 \times \cancel{1.2}}{ \cancel{1.2}} [/tex]

[tex] \sf \implies t = 7 \: s[/tex]

Answer:

a

   [tex]f = 0.4848 \ m[/tex]

b

  [tex]p = 2.063 D[/tex]

Explanation:

From the question we are told that

   The  near point distance is  [tex]k = 45.5 \ cm[/tex]

    The  distance of the glasses from the eye is  [tex]y = 2.1 \ cm[/tex]

    The  distance of an object she can focus with the glass is  [tex]i= 25 \ cm[/tex]

Generally the image distance is mathematically evaluated  as

     [tex]v = -(45.5 - 2.1)[/tex]

     [tex]v = -43.4 \ cm[/tex]

Generally the object distance is mathematically represented as

     [tex]u = (25 -2.1)[/tex]

     [tex]u = 22.9 \ cm[/tex]

The  negative sign tells us that the image was formed behind the eye  

Generally the lens formula  is mathematically represented as  

        [tex]\frac{1}{f} = \frac{1}{u} + \frac{1}{v}[/tex]

=>   [tex]\frac{1}{f} = \frac{1}{22.9} + \frac{1}{ - 43.4}[/tex]

=>  [tex]f = 48.48 \ cm[/tex]

 converting to meters  

   [tex]f = 0.4848 \ m[/tex]

Thus the refractive power is mathematically represented as

    [tex]p = \frac{1}{f}[/tex]

=>  [tex]p = \frac{1}{0.4848 }[/tex]

=>   [tex]p = 2.063 D[/tex]

Answer:

d poor accuracy,poor precision

The diagram represents how much accurate and precise the result data is. It is clear from the image that, the data points have poor accuracy and good precision.

Accuracy of a result is the measure of the closeness of the experimental or calculated value to the true value or absolute value of a measurement.  For a reproducible experiment, the results for each trials can be differ or close.

The closeness between values of a set of experiments is called precision of the results. Not all accurate value be can be precise. Similarly precision of values does not need to meet accuracy.

Here, the central dot indicates the true value. The green points are a set of experimental values. They are not so close to the true value and hence it is less accurate. However, all the points and closer together. Hence, they are precise. Therefore, option B is correct.

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Answer:

52.7 m

Explanation:

Given that

speed of the vehicle, v = 95 km/h

time of inattentiveness, t = 2 s

distance travelled, s = ?

Since we have the speed in km/h and the time in s, it would be best if we converted one of them to make sure we have all units in the same rank.

95 km/h = 95 * 1000/3600 m/s

95 km/h = 95000/3600 m/s

95 km/h = 26.38 m/s

Now, we use our derived speed in m/s

Speed of a moving vehicle is given by,

v = s/t, where

v = speed in m/s

s = distance travelled, in m

t = time spent, in s

if we make d the subject of formula by rearranging the equation, we have

s = v * t

distance travelled, s = 26.38 * 2

distance travelled, s = 52.7 m

therefore, during this inattentive period, 52.7 m was travelled.

Conductivity is the property of matter in which a substance can transfer heat or electricity.

Matter : Anything which occupies space and has mass is called matter.

Chemical classifications

Physical classifications

The angular acceleration of the tires is -2.2 rad/s².

If the car continues to decelerate at this rate, the time required to stop is 27.66 s.

The total distance traveled by the car before stopping is 210.96 revolutions.

The given parameters;

The angular acceleration of the tire is calculated as follows;

[tex]\omega _f^2 = \omega _i ^2 + 2\alpha \theta\\\\(\frac{16.67}{0.42} )^2 = (\frac{25.56}{0.42} )^2 + 2( 77 \ rev \times \frac{2 \pi \ rad}{1 \ rev} ) \alpha \\\\1575.33 = 3703.59 \ + \ 967.736 \alpha \\\\-2128.26 = 967.736 \alpha\\\\\alpha = \frac{-2128.26}{967.736} \\\\\alpha = - 2.2 \ rad/s^2[/tex]

When the car stops, the final angular speed = 0. The time for the motion is calculated as;

[tex]\omega _f = \omega _i + \alpha t\\\\0 = \omega _i + \alpha t\\\\0 = 60.86 + (-2.2)t\\\\0 = 60.86 - 2.2t\\\\2.2t = 60.86\\\\t = \frac{60.86}{2.2} \\\\t = 27.66 \ s[/tex]

The total distance traveled by the car before stopping;

[tex]\theta = \omega_i t + \frac{1}{2} \alpha t^2\\\\\theta = (60.86 \times 27.66) \ + \ (0.5 \times -2.2\times 27.66^2)\\\\\theta = 841.8 \ rad\\\\\theta = 841.8 \ rad \times\frac{1 \ rev}{2\pi \ rad} = 133.96 \ rev[/tex]

total distance = 133.96 + 77 = 210.96 revolutions.

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Answer:

The switching rate between the steady state and the normal state of a capacitor

Explanation:

This was a hard one! Could only find it in my textbook. Anyways this basically is the rate which the capacitors switches back from steady state and normal state from when it charges and discharges over time. This has many purposes as a special type of diode or any other transistor type device etc etc.

Answer:

L = L0 ( 1 - v^2/c^2))1/2     where L0 is the proper length

L = 10 L-y (1 - .9^2)^1/2 = 4.36 L-y   length of pole measured by ship

t = 4.36 L-y / .9 c = 4.84 y  since the ship travels at .9 c

Answer:

The correct treatment of uncertainties for the volume is shown below

Explanation:

In order to estimate the uncertainty in the volume which is derived via the formula:

[tex]V = w*l*h[/tex]

you normally start with the relative errors  [tex](\frac{\delta Q}{Q})[/tex]  of each quantity (Q) measured, since they are so easy to handle, stating that the relative error in the Volume is the addition of the relative errors in each quantity:

[tex]\frac{\delta V}{V} =\frac{\delta w}{w} +\frac{\delta l}{l} +\frac{\delta h}{h}[/tex]

and finally solve for [tex]\delta V[/tex] by multiplying both sides by the volume you calculated.

In your case, this becomes:

[tex]\delta V =V \left \{\frac{\delta w}{w} +\frac{\delta l}{l} +\frac{\delta h}{h}\right \} \\\delta V = 244.296 \left \{\frac{0.1}{5.4} +\frac{0.1}{8.7} +\frac{0.1}{5.2}\right \}\\\delta V = 244.296 \, (0.04924354)\\\delta V = 12.03 \,\,cm^3[/tex]

Then, since the standard practice is to write the uncertainty with ONLY ONE significant figure, the rounding of your uncertainty becomes:

[tex]\delta V=10\,\,cm^3[/tex]

Giving this, you need to express the final measurement as:

[tex]V=240\,\,cm^3\,+/- 10 \,\,cm^3[/tex]

making sure that the expression for the volume doesn't have significant figures passed the limitation imposed by its uncertainty (in this case the tenths).

Please notice as well that in the treatment you did, you:

1) ended up with an uncertainty even smaller than the relative uncertainty of each measurement (which cannot be possible since relative uncertainties add-up)

2) are not rounding your uncertainty to ONE SIG FIG.

Answer:

Given that K.E is

1/2mv²

So to find speed v,

Make it subject

K.E= 1.2mv²

However radial force = magnetic force

So mv²/r= qvB

So v subject

V= 2K.E/ qBr that is speed

To find mass

K.E = 1/2mv²

Puy value of v

So KE= 1/2m(2K.E/qBr)

m= (qBr)/2K.E

That is mass

Answer:

m = qbr/v

v = 2k/qbr

Explanation:

When a charged particle enters a magnetic field, it experiences a force that is always perpendicular to the velocity. This force provides a centripetal force, and thus, we have

qvb = mv²/r

if we make m the subject of the formula, we will have

m = qbr/v

Recall that the kinetic energy, KE = ½mv²

Now, let's make v² the subject of formula, we have

v² = 2K/m

now, we substitute for m from the equation we got earlier

v² = 2K / (qbr/v)

v² = 2Kv / qbr, if we simplify further, we have

v = 2k / qbr

Therefore, we can say that the expression for the mass and speed is respectively,

m = qbr/v

v = 2k/qbr