Which refers to any disturbance that carries energy from one place to another through matter and space?

frequency
wave
hertz
pitch

Answer: The amount of time it takes for half of the material to decay

B. The time needed for half of a sample of radioisotope to decay is the half-life of a radioisotope.

Radioactive decay is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive.

The most common types of decay are alpha decay, beta decay, and gamma decay, all of which involve emitting one or more particles.

The radioactive half-life means, the time required for half the atoms of a particular radioisotope to decay into another isotope.

The half-life of a radioactive isotope is the amount of time it takes for one-half of the radioactive isotope to decay.

The half-life of a specific radioactive isotope is constant; it is unaffected by conditions and is independent of the initial amount of that isotope.
Therefore,

The half-life of a radioisotope is the time needed for half of a sample of radioisotope to decay.

The correct option is B

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Answer:

57°

Explanation:

Etienne Malus discovered the idea of polarization by reflection. If light is incident on a surface at an angle of 57°, the reflected ray is found to be plane polarized.

Hence, with respect to the normal to the interface, light incident at 57° is completely polarized.

Answer:

526.5m

Explanation:

Given parameters:

Acceleration = 3m/s²

Initial velocity  = 21m/s

Final velocity  = 60m/s

Unknown:

Displacement = ?

Solution:

To solve this problem, we apply the right motion equation which is shown below;

     V²  = U²  + 2aS

  V is the final velocity

  U is the initial velocity

  a is the acceleration

 S is the displacement

 Insert the parameters and solve;

    60²  = 21² + 2(3)S

    3600 = 441 + 6S

    3600 - 441  = 6S

    3159  = 6S

       S = 526.5m

ANSWER

Lift frame :

Initial speed of the coin u=0 m/s

Acceleration a=9.8 m/s

2

Initial height of coin from the floor of elevator h=2.45 m

Time taken by coin to hit the floor T=

g

2H

⟹ T=

9.8

2×2.45

=

2

1

s

velocity of the lift (u₁) = 10 m/s

initial velocity of the coin (u₂) = 10 m/s  

(the coin is also moving with the Elevator)

acceleration of the coin (a₂) = -9.8 m/s²

acceleration of the Elevator (a₁) = 0 m/s

Distance covered by the coin (s)  = -2.5 m

__________________________________________________________

Relative velocity:

We will find the velocity and acceleration of the coin with respect to the lift since we are monitoring the motion of the coin

velocity of the coin with respect to the elevator (u₂₁) = u₂ - u₁

u₂₁ = 10 - 10

u₂₁ = 0m/s

Relative Acceleration:

acceleration of the coin with respect to the elevator (a₂₁) = a₂ - a₁

a₂₁ = -9.8 - 0

a₂₁ = -9.8

__________________________________________________________

From the second equation of motion, we know that:

s=  ut + 1/2at₂

we can rewrite this equation in terms of relative motion:

s = u₂₁(t) + 1/2(a₁₂)t²  

Notice that the time and the displacement are not relative, that's because displacement and time will remain the same no matter the frame of reference

replacing the known values in the equation:

-2.5 = (0)(t) + 1/2 (-9.8)(t²)

-2.5 = -4.9(t²)

dividing both sides by -4.9

t² = -2.5 / -4.9

t² = 25/49

t² = (5)² / (7)²

taking the square root of both the sides

t = 5/7   OR   0.71 seconds (approx)

Therefore, the coin will reach the floor of the Elevator in 0.71 seconds

Answer:

c

Explanation:

The lamp lights up using electrical power, and so the light bulb heats up.

Answer:a

Explanation:

i took the test

Answer:

225nm

Explanation:

The Maxima of diffraction girating

dsin( θ)= m(λ)

Where θ)= angle between central axis and corresponding point

The wavelength is to corresponding sin( θ)

Then the maximum number of (λ) can be seen by setting sin( θ)= 1 then

d= m(λ)

At fifth order maximum m=1 then

d= 5(λ)

Where d= distance between the slit and with girating of 1/890rullig/mm

d= 1/890rullig/mm= 8.90×10^-6m

At maximum wavelength

d= 5(λ)

(λ)=5/d

= 8.90×10^-6m/5

=2.75*10^-7

= 275nm

Therefore, longest wavelength that forms an intensity maximum in the fifth order is 275nm

Answer:

22.4 s

Explanation:

The following data were obtained from the question:

Mass (m) = 75 Kg

Height (h) = 50 ft

Power (P) = 500 W

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) =?

Next, we shall convert 50 ft to metres (m). This can be obtained as follow:

1 ft = 0.3048 m

Therefore,

50 ft = 50 ft × 0.3048 m / 1 ft

50 ft = 15.24 m

Thus, 50 ft is equivalent 15.24 m.

Next, we shall determine the energy used by the student to walk up three flights of stairs. This can be obtained as follow:

Mass (m) = 75 Kg

Height (h) = 15.24 m

Acceleration due to gravity (g) = 9.8 m/s²

Energy (E) =?

E = mgh

E = 75 × 9.8 × 15.24

E = 11201.4 J

Finally, we shall determine the time taken for the student to travel up the three flights of stairs. This can be obtained as follow:

Power (P) = 500 W

Energy (E) = 11201.4 J

Time (t)

Power (P) = Energy (E) / Time (t)

500 = 11201.4 /t

Cross multiply

500 × t = 11201.4

Divide both side by 500

t = 11201.4 /500

t = 22.4 s

Therefore, it will take the student 22.4 s to travel up the three flights of stairs.

The time taken for the student to travel up the three stairs is 22.4 s.

The given parameters;

The gravitational potential energy of the student due to vertical position of the three stairs is calculated as;

[tex]P.E = mgh\\\\P.E = 75 \times 9.8 \times 15.24 \\\\P.E =11,201.4 \ J[/tex]

The time taken for the student to travel up the three stairs is calculated as follows;

[tex]E = Pt\\\\t = \frac{E}{P} \\\\t = \frac{11,201.4}{500} \\\\t = 22.4 \ s[/tex]

Thus, the time taken for the student to travel up the three stairs is 22.4 s.

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Answer:

860 km

Explanation:

430*2=860

Answer:

a) Pabs = 345.7 [kPa]

b) F = 278.08 [N]

Explanation:

Manometric pressure in liquids is defined as the product of density by gravitational acceleration by the height of the liquid.

[tex]P_{g} =Ro*g*h[/tex]

where:

Pg = manometric pressure [Pa]

Ro = density = 0.890*10³[kg/m³]

g = gravity acceleration = 9.81 [m/s²]

h = liquid height = 28 [m]

Now the absolute pressure is defined as the sum of the atmospheric pressure plus the manometric pressure

a)

[tex]P_{abs}=P_{man}+P_{gau}\\P_{abs}= 101300 + (890*9.81*28)\\P_{abs} = 345765.2 [Pa] = 345.7 [kPa][/tex]

b) To determine the force at that point

The pressure is now defined as the relationship of a force over the area.

[tex]P=F/A\\F = P*A\\[/tex]

But the area of a circle can be calculated as follows:

[tex]A=\frac{\pi }{4} *(0.032)^{2}\\A = 0.0008042[m^{2}] \\F = 345765.2*0.0008042\\F = 278.08 [N][/tex]

Answer:

I'm pretty sure that the answer is C. Hope this helps.

Explanation:

Answer:

Answer is A. Under any conditions

Explanation:

Just got it correct on A p e x

Answer: it’s the diagram with a small tree on one side and a larger tree on the other side.

The ray diagram that shows the proper positioning of the image is: the first diagram, where the image is smaller than the object.

A concave mirror also known as converging mirror is a type of curved or spherical mirror in which the outside surface is silvered and the inner surface is made to reflect.

The size and the nature of the image of this kind of mirror is relatively dependent on the position of the object with regards the mirror.

Analysis:

When the object is behind the centre of curvature, the  image is seen to be real, inverted and smaller than the object.

So, the image of the concave mirror increases in size as the object gets closer to the centre of curvature and would be same size as the object at the centre of curvature.

In conclusion, the ray diagram that shows the proper positioning of the image is the first diagram.

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Answer:

Sun heating a car sitting in a parking lot

Explanation:

The sun heating a car sitting in a parking lot is an example of electromagnetic waves transferring energy.

Answer:

d

Explanation:

Answer:

1.67m

5m/s

Explanation:

Given parameters:

Wavelength of the wave = 3m

Speed of the wave  = 5m/s

Unknown:

Frequency of the wave  = ?

Speed of the water waves  = ?

Solution:

The distance between crest and the adjacent trough of water waves is known as the wavelength of a wave.

  To find the frequency ;

         V = f∧

V is the speed of the wave

f is the frequency

∧ is the wavelength

   Insert the parameters and find the frequency;

         f  = V/ ∧   = 5 / 3  = 1.67Hz

The rate at which the wave passed a given point is the speed of the wave and it is 5m/s

Answer:

After 30 minutes, the temperature of the body is: T₁₀ = 311.60 K

After 60 minutes, the temperature of the body is: T₂₀ = 298.18 K

Explanation:

Given that:

[tex]\dfrac{dT}{dt}= K \bigg [ M(t) -T(t)\bigg][/tex]

where;

K = 0.04

M(t) = 293

Then;

[tex]\dfrac{dT}{dt}= 0.04 \bigg [ 293 -T\bigg][/tex]

[tex]\dfrac{dT}{dt}= 11.72 -0.04 \ T[/tex]

Using Euler's Formula;

[tex]T_{n+1} = T_n + hf( t_n, T_n)[/tex]

where;

[tex]f(t_n,T_n) = 11.72 - 0.04 T_n[/tex]

Then;

[tex]T_{n+1} = T_n + 3.0 (11.72-0.04 \ T_n)[/tex]

[tex]T_{n+1} = 0.88T_n + 35.16 \ ---(1)[/tex]

At initial state [tex]t_0[/tex]  (0);  [tex]T_0[/tex] = 360

At t₁ = 3.0 when T₀ = 360

[tex]T_1= 0.88 T_o + 35.16[/tex]

[tex]T_1= 0.88 (360) + 35.16[/tex]

[tex]T_1 = 351.96 \ K[/tex]

At t₂ = 6.0 when T₂ = 0.88T₁ + 35.16

T₂ = 0.88(351.96) + 35.16

T₂ = 344.89 K

At t₃ = 9.0 when T₃ = 0.88T₂ + 35.16

T₃ = 0.88(344.89) + 35.16

T₃ =338.66 K

At t₄ = 12.0 when T₄ = 0.88T₃ + 35.16

T₄ = 0.88(338.66) + 35.16

T₄ = 333.18 K

At  t₅ = 15.0 when T₅ = 0.88T₄ + 35.16

T₅ = 0.88(333.18) + 35.16

T₅ = 328.36 K

At t₆ = 18.0 when T₆ =  0.88T₅ + 35.16

T₆ = 0.88(328.36) + 35.16

T₆ = 324.12 K  

At t₇ = 21.0 when T₇ = 0.88T₆ + 35.16

T₇ = 0.88(324.12) + 35.16

T₇ = 320.39 K

At t₈ = 24.0 when T₈ = 0.88T₇ + 35.16

T₈ = 0.88(320.29) + 35.16

T₈ = 317.02 K

At t₉ = 27.0 when T₉ = 0.88T₈ + 35.16

T₉ = 0.88(317.02) + 35.16

T₉ = 314.14 K

At t₁₀ = 30 when T₁₀ = 0.88T₉ + 35.16

T₁₀ = 0.88(314.14) + 35.16

T₁₀ = 311.60 K

At t₁₁ = 33.0 when T₁₁ = 0.88T₁₀ + 35.16

T₁₁ = 0.88(311.60) + 35.16

T₁₁ = 309.37 K

At t₁₂ = 36.0  when T₁₂ = 0.88T₁₁ + 35.16

T₁₂ = 0.88(309.37)+ 35.16

T₁₂ = 307.41 K

At t₁₃ = 39.0  when T₁₃ = 0.88T₁₂ + 35.16

T₁₃ = 0.88( 307.41) + 35.16

T₁₃ = 305.68 K

At t₁₄ = 42.0  when T₁₄ = 0.88T₁₃ + 35.16

T₁₄ = 0.88(305.68) + 35.16

T₁₄ = 304.16 K

At t₁₅ = 45.0  when T₁₅ = 0.88T₁₄ + 35.16

T₁₅ = 0.88(304.16) + 35.16

T₁₅ = 302.82 K

At t₁₆ = 48.0  when T₁₆ = 0.88T₁₅ + 35.16

T₁₆ = 0.88(302.82) + 35.16

T₁₆ = 301.64 K

At t₁₇ = 51.0  when T₁₇ = 0.88T₁₆ + 35.16

T₁₇ = 0.88(301.64) + 35.16

T₁₇ = 300.60 K

At t₁₈ = 54.0  when T₁₈ = 0.88T₁₇ + 35.16

T₁₈ = 0.88(300.60) + 35.16

T₁₈ = 299.69 K

At t₁₉ = 57.0  when T₁₉ = 0.88T₁₈ + 35.16

T₁₉ = 0.88(299.69) + 35.16

T₁₉ = 298.89 K

At t₂₀ = 60  when T₂₀ = 0.88T₁₉ + 35.16

T₂₀ = 0.88(298.89) + 35.16

T₂₀ = 298.18 K

Answer:

12s

Explanation:

Given parameters:

Velocity  = 7.5m/s

Distance  = 90m

Unknown:

Time taken  = ?

Solution:

Speed is the rate of distance traveled with time. It is mathematically expressed as;

      Speed  = [tex]\frac{distance}{time}[/tex]

Since the unknown is time;

        Time  = [tex]\frac{distance}{speed}[/tex]  

      Insert the parameters and solve;

  Time  = [tex]\frac{90}{7.5}[/tex]   = 12s

Answer:

27.0 milliliters is the nearest mililiter so 27.0 is the answer

Explanation:

Answer:

Because it was too hot for volatile compounds (like water) to condense in the inner solar system, rocky planetesimals formed from compounds with high melting points, such as iron and rocky silicates

Answer:

0.77 m/s^2

Explanation:

Notice that the weight of the 7 kg mass is calculated via:

weight = m * g = 7 * 9.8 N = 68.6 N

Since the tension in the string is larger (74 N), then the elevator is moving upward and the net force on the object is equal to:

74 N - 68.6 N =  5.4 N

Which tells us that the acceleration of the object is:

F = m * a

5.4 N = 7 kg * a

a = 5.4 /7  m/s^2

a = 0.77 m/s^2

and this must be the same as the acceleration of the elevator since object and elevator are moving together.

Answer:

its y

Explanation:

Answer:

a. The initial velocity will decrease until it reaches its final velocity/maximum (which is 0).

b. The acceleration always remain constant.

Explanation:

Nuclear energy is argued to be renewable because it is found in the atoms that make up the earth, does not emit carbon and its use can be made unlimited by the use of technologies.

Answer:

Nuclear energy is a non-renewable energy source that comes from the nucleus of atoms.

Answer:

short circuit

Explanation:

A disrupted circuit in which the current bypasses its proper path is a short circuit.

A short circuit is an electrical circuit which allows the electric current to travel along an unintended and uninterrupted path with no or very low electrical impedance in the circuit. This results in an excessive current flow through the electric circuit.

A short circuit is a situation in which there is  faulty connection or damaged wire that causes electric current to travel along the wrong route in the circuit with low or no resistance and damage an electrical device. This may cause serious damage, fire, or even small-scale explosions.

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Answer:

3.38m

Explanation:

Given parameters:

Time  = 4s

Acceleration  = 1.3m/s²

Unknown:

Magnitude of the displacement = ?

Solution:

The body starts at rest and the initial velocity is 0m/s. To solve this problem, we have to use the expression below;

    S   = Ut  + [tex]\frac{1}{2}[/tex]at²

 S  = displacement

t is the time

  a is the acceleration

  U is the initial velocity

  V is the final velocity

Insert the parameters and solve;

   S = (0 x 4)  +  [tex]\frac{1}{2}[/tex] x 1.3² x 4  = 3.38m

Bandura's social learning theory, imitation, and observation are the two main ways that people pick up new skills. Bandura's theory encompasses more than just the notion that interaction with the environment leads directly to learning.

According to Bandura, hostility can also be learned indirectly through observational learning. According to the social learning theory, children learn through imitation.

An individual will internalize and replicate the aggressive behaviors of a role model in the future.

According to Bandura social learning theories, children pick up aggressive behaviors via watching others act aggressively and seeing how these actions are reinforced over time.

Therefore,  it is false  being punished were far more likely to be aggressive than children who did not.

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Answer:

v = 7.69 x 10³ m/s = 7690 m/s

T = 5500 s = 91.67 min = 1.53 h

Explanation:

In order for the satellite to orbit the earth, the force of gravitation on satellite must be equal to the centripetal force acting on it:

[tex]F_{gravitation}= F_{centripetal}\\\\\frac{GM_{s} M_{E}}{r^2} = \frac{M_{s} v^2}{r}\\\\\frac{GM_{E}}{r} = v^2\\\\v = \sqrt{\frac{GM_{E}}{r} } \\\\[/tex]

where,

G = Universal Gravitational Constant = 6.67 x 10⁻¹¹ N.m²/kg²

Me = Mass of Earth = 5.97 x 10²⁴ kg

r = distance between the center of Earth and Satellite = Radius of Earth + Altitude = 6.371 x 10⁶ m + 0.361 x 10⁶ m = 6.732 x 10⁶ m

v = orbital speed = ?

Therefore,

[tex]v = \sqrt{\frac{(6.67 x 10^{-11}N.m^2/kg^2)(5.97 x 10^{24} kg)}{6.732 x 10^6 m} }\\\\[/tex]

v = 7.69 x 10³ m/s

For time period satellite completes one revolution around the earth. It means that the distance covered by satellite is equal to circumference of circle at the given altitude.

So, its orbital speed can be given as:

[tex]v = \frac{Circumference of Circle at Given Altitude}{T}\\\\v = \frac{2\pi r}{T}\\\\[/tex]

where,

T = Time Period of Satellite = ?

Therefore,

[tex]T = \frac{2\pi r}{v}\\\\T = \frac{(2\pi )(6.732 x 10^6 m}{7.69 x 10^3 m/s}\\\\[/tex]

T = 5500 s = 91.67 min = 1.53 h

Explanation:

Q1) What is the speed of the tip of the minute hand of a clock where the hand is of length 7cm?

Ans1) speed, v=st=2πrT=2×227×7×10-260×60=119×10-4=1.22×10-4m/s

Answer:

a. 0.32 b. 1448 m/s

Explanation:

We know v ∝ √T where v = velocity of sound and T = absolute temperature.

Let v₁ = velocity of sound at 17°, v₁ = fλ where f = frequency of sound = 512 Hz and λ = 66.5 cm = 0.665 m

So, v₁ = fλ = 512 Hz × 0.665 m = 340.48 m/s

T₁ = 17 + 273 = 290 K

Let v₂ = velocity of sound in air at NTP = unknown and T₂ = temperature at NTP = 0°C + 273 = 273 K

Now v₁/v₂ = √T₁/√T₂

So, v₂ = (√T₂/√T₁)v₁

= [√(T₂/T₁)]v₁

substituting the values of the variables, we have

v₂ =  [√(273 K/290 K)]340.48 m/s

v₂ =  [√0.9413]340.48 m/s

v₂ = (0.9702)340.48 m/s

v₂ = 330.35 m/s

Also v = √(γP/ρ) where v = velocity of sound in air at NTP  = 330.35 m/s, γ = ratio of molar heat capacities, P = pressure at NTP = 1.013 × 10⁵ Pa and ρ = density of air = 1.293 kg/m³

Since,  v = √(γP/ρ)

making γ subject of the formula, we have

γ = v²ρ/P

substituting the values of the variables, we have

γ = (330.35 m/s)² × 1.293 kg/m³/1.013 × 10⁵ Pa

= 31975.36 kg/m²s² ÷ 1.013 × 10⁵ Pa

= 0.32

b. Speed of sound in mercury v₃ = √(B/ρ) where B = Bulk modulus of mercury = 28.5 × 10⁹ Pa and ρ = density of mercury = 13600 kg/m³

v₃ = √(B/ρ)

= √(28.5 × 10⁹ Pa/13600 kg/m³)

= √(28.5 × 10⁹ Pa/13.6 × 10³ kg/m³)

= √(2.096 × 10⁶) m/s

= 1.448 × 10³ m/s

= 1448 m/s

Answer:

Have a great day!

Explanation:

Barometers. A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure.

Answer:

atmospheric  pressure

Explanation: