A student of mass 45kg, who is undergoing National Service training, takes 6s to climb a flight of stairs that had 36 steps. If each step is 16cm high, what is the power of the student?

Answers

Answer 1

Answer:

Approximately [tex]4.2 \times 10^{2}\; \rm W[/tex] on average in the vertical direction (assuming that [tex]g = 9.8\; \rm N \cdot kg^{-1}[/tex].)

Explanation:

Vertical displacement of this student in [tex]6\; \rm s[/tex]: [tex]36 \times 16\; \rm cm = 36 \times (0.16\; \rm m) = 5.76\; \rm m[/tex].

Average vertical velocity of this student: [tex]v = \displaystyle \frac{5.76\; \rm m}{6\; \rm s} = 0.96\; \rm m \cdot s^{-1}[/tex].

The average vertical force that this student exerts on the ground would be equal to the weight of this student:

[tex]F = W = m \cdot g = 45\; \rm kg \times 9.8\; \rm N \cdot kg^{-1} = 441\; \rm N[/tex].

The average power of this student in the vertical direction is equal to the product of the force and velocity of this student in that direction:

[tex]P = F \cdot v = 441\; \rm N \times 0.96\; \rm m \cdot s^{-1} \approx 4.2\times 10^{2}\; \rm W[/tex].


Related Questions

Two waves, each with an amplitude of 0.5m are superimposed with constructive interference such that they are in phase. Describe the resultant amplitude

Answers

The resultant amplitude of the two waves is 1.0m

Interference occurs when two or more waves are superimposed over each other.

These waves can either be destructive or constructive in nature. If the waves are superimposed with constructive interference such that they are in phase, the resultant amplitude will be the sum of the amplitude of both waves.

Resultant amplitude = 0.5m + 0.5m

Resultant amplutude = 1.0m

Hence the resultant amplitude of the two waves is 1.0m

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What is the process called when heat transfers through space in the form of radiation?

Answers

Answer:

Insolation

Explanation:

It's actually the process when heat is transferred from the sun to the surface of the earth

A toy gun uses a spring to shoot plastic balls (m = 50 g). The spring is compressed by 3.0 cm. Let k=2.22 × 105 N/m. (a) Of course, you have to do some work on the gun to arm it. How much work do you have to do? (b) Suppose you fire the gun horizontally. How fast does the ball leave the gun? (c) Now suppose you fire the gun straight upwards. How high does the ball go?

Answers

Answer:

Explanation:

Given that:

mass of the plastic ball = 50 g = 50 × 10⁻³ kg

spring constant (k) = 2.22 × 10⁵ N/m

compression of spring (x) = 3.0 cm = 3 × 10⁻² m

a) Work done:

[tex]= \dfrac{1}{2}kx^2 \\ \\ = \dfrac{1}{2}\times 2.22 \times 10^{5}\times (3 \times 10^{-2})^2 \\ \\ = 99.9 \ J[/tex]

b) When the gun is fired horizontally;

In the spring, the potential energy is changed to kinetic energy.

i.e.

[tex]\implies \dfrac{1}{2}kx^2 = \dfrac{1}{2}mv^2 \\ \\ 2.22 \times 10^5 \times (3\times 10^{-2}) ^2 =50 \times 10^{-3} \times v^2\\ \\ \mathbf{v= 63.2 m/s}[/tex]

c) The max height the bullet will reach if the gun is being shot upward is:

[tex]H_{max}= \dfrac{v^2}{2g} \\ \\ H_{max}= \dfrac{63.2^2}{2\times 9.8}[/tex]

[tex]\mathbf{H_{max}= 203.9 \ m}[/tex]

Which statement is true of an alpha particle?

A. It is electromagnetic radiation, not a true particle.

B. It is an electron.

C. It is the largest decay particle

D. It is a particle that travels at the speed of light.​

Answers

Answer:

Atoms are made up of various parts; the nucleus contains minute particles ... neutrons, and the atom's outer shell contains other particles called electrons. ... Physical Forms of Radiation; Radioactive Decay; Nuclear Fission; Ionizing Radiation ... of high-energy waves that can travel great distances at the speed of light and ...

Explanation:

The true statement of an alpha particle is it is an electron. The correct option is B.

What is an alpha particle?

The alpha particle are composite particles which consists of two protons and two neutrons tightly bonded together. They are ejected from the inside the nucleus of heavy radioactive particles, also called alpha decay.

Atoms are made up electrons orbiting in outer shells, protons and neutrons in the nucleus. The radioactive particle emit highly ionized radioactive rays which ionize electrons emitting alpha particle.

Thus, the correct option is B.

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Which of the following ways of writing 1000w is incorrect?
1) 1 kW
2) 1 x 10³ W
3) 10 x 10³ W
4) 1.0 x 10³ W

Answers

Answer:

the third one is incorrect

Explanation:

10 x 10³= 10^1 x 10^3 = 10^4

Is this right? Please help me ITS SOCIOLOGY

Answers

Yes, this is correct Answer.

how do you know which magnitude is higher or how do you compare them?

Answers

Magnitudes are measured by intensity so a 3.4 earthquake is much less stronger than a 4.5 earthquake it’s very literally when measuring them the higher the number the stronger it is

HELP pleaseee which nucleus completes the following equation?

Answers

Answer:

its D

Explanation:

i just got it correct on a. p. e. x. :)

state and explain the disadvantages of anomalous expansion of water​

Answers

Answer:

я не знаю старайся изо всех сил

Explanation:

[tex]\huge{\mathbb{\tt { QUESTION↓}}}[/tex]

[tex]\color{green}{\tt State \: and \: explain \: the \: disadvantages}[/tex]

[tex]\color{green}{\tt { of \: anomalous \: expansion \: of \: water}}[/tex]

[tex]\huge{\mathbb{\tt {ANSWER↓}}}[/tex]

[tex]{\boxed{\boxed{\tt { DISADVANTAGES \: of \: anomolous \: expansion \: of \: water }}}}[/tex]

Since the maximum density can be found for a positive temperature, water's own weight will prevent it from freezing from the bottom up. However, the anomalous expansion of water has some negative consequences. ... As the water freezes it expands and can rip pipes open.

[tex]{\boxed{\boxed{\tt { What \: is \: the \: state \: of \: anomalous \: expansion \: of \: water? }}}}[/tex]

The anomalous expansion of water is an abnormal property of water whereby it expands instead of contracting when the temperature goes from 4o C to 0o C, and it becomes less dense. The density is maximum at 4 degree centigrade and decreases below that temperature as shown in graph

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A truck with a mass of 15,000 kg moving at 25 m/s crashes into the back of a small 1,100 kg car moving at 15 m/s. They
stick together after the collision. Calculate the momentum of the system before the collision and after the collision.

Answers

Explanation:

Given that,

Mass of a truck = 15,000 kg

Speed of the truck = 25 m/s

Mass of car = 1,100 kg

Speed of the car = 15 m/s

As they stick together after the collision. Let V be the speed after the collision.

Initial momentum of the system,

[tex]P_i=15000\times25+1100\times15\\\\=391500\ kg-m/s[/tex]

Final momentum of the system,

[tex]P_f=(15000+1100)V\\\\=16100V[/tex]

Hence, this is the required solution.

A boy who is riding his bicycle, moves with an initial velocity of 5 m/s. ten second later, he is moving at 15 m/s. what is his acceleration

Answers

Answer:

1 m/s²

Explanation:

From the question,

Using

a = (v-u)/t.................... Equation 1

Where a = accelartion of the bicycle, v = Final velocity, u = initial velocity, t = time.

Given: v = 15 m/s, u = 5 m/s, t = 10 s

Substitute these values into equation 1

a = (15-5)/10

a = 10/10

a = 1 m/s²

Hence the acceleration of the bicycle is 1 m/s²

What specific type of tide has the smallest difference between high and low tide?

Answers

Answer: Neap tides

Explanation: Neap tides are tides that have the smallest tidal range, and they occur when the Earth the Moon, and the Sun form a 90o angle. They occur exactly halfway between the spring tides when the Moon is at first or last quarter.

Calculate the refractive index for a substance where the angle of incidence is 300 , the angle of refraction is 600 , and the refractive index of second substance is 1.5

Answers

Answer:

η₁ = 2.6

Explanation:

Here, we will use snell's law to calculate the refractive of the substance:

[tex]\frac{\eta_2}{\eta_1} = \frac{Sin\theta_1}{Sin\theta_2}[/tex]

where,

η₁ = refractive index of first substance = ?

η₂ = refractive index of second substance = 1.5

θ₁ = angle of incidence = 30°

θ₂ = angle of refraction = 60°

Therefore,

[tex]\frac{1.5}{\eta_1} = \frac{Sin\ 30^0}{Sin\ 60^0}[/tex]

η₁ = 2.6

Please Help Me!!!
Water is a colorless and odorless liquid. It can exist in solid, liquid, and gas states. It boils at 100 degrees C and melts at 0 degrees C.
Which option best describes this information?
A.
These are the physical properties of water.
B.
These are the chemical properties of water.
C.
These are the physical changes water undergoes.
D.
These are the chemical changes water undergoes.
E.
These are the molecular changes water undergoes.

Answers

Answer:

There are the molecular changes water undergoes

Calculate the Kinetic energy of: 1. a rabbit weighing 10
kg moving at a speed of 5 m/s.

Answers

Answer:

125

Explanation:

use the formula e=1/2mv² and use m=10 and v=5

this produces the equation e=1/2x10x25=125

dont forget the units (J) ;)

Answer:

125J

Explanation:

K.e=1/2mv^2

=1/2(10)(5)^2

=125J

Why did the lemon battery work and how many volts does one produce?
O The juice of the lemon is an acid and the acid caused 2 volts.
O The juice of the lemon is an electrolytic solution allowing electrons to flow and created around 5 V.
O The juice of the lemon is an electrolytic solution allowing electrons to flow and created around 1.5 V.
O The juice of the lemon is an acid and the acid caused 1 volt.

Answers

Answer:

the third one

Explanation:

A decibel measures the _____________ of sound.

A.pitch

B,frequency

C.loudness

D.amplitude

Answers

Decibels measure sound intensity- which would be D. Amplitude.

someone please helppp :|||

Answers

Answer:

b

Explanation:

Answer:

its c

Explanation:

i have asked my teacher

The 4kg head of a sledge hammer is moving at 6m/s when it strikes a chisel, driving it into a log. The duration of the impact (or the time for the sledge hammer to stop after contact) is 0.0020s. Find the time average of the impact force

Answers

Answer:

The average impact force is 12000 newtons.

Explanation:

By Impact Theorem we know that impact done by the sledge hammer on the chisel is equal to the change in the linear momentum of the former. The mathematical model that represents the situation is now described:

[tex]\bar F \cdot \Delta t = m \cdot (v_{2}-v_{1})[/tex] (1)

Where:

[tex]\bar F[/tex] - Average impact force, in newtons.

[tex]\Delta t[/tex] - Duration of the impact, in seconds.

[tex]m[/tex] - Mass of the sledge hammer, in kilograms.

[tex]v_{1}[/tex], [tex]v_{2}[/tex] - Initial and final velocity, in meters per second.

If we know that [tex]\Delta t = 0.0020\,s[/tex], [tex]m = 4\,kg[/tex], [tex]v_{1} = -6\,\frac{m}{s}[/tex] and [tex]v_{2} = 0\,\frac{m}{s}[/tex], then we estimate the average impact force is:

[tex]\bar F = \frac{m\cdot (v_{2}-v_{1})}{\Delta t}[/tex]

[tex]\bar F = 12000\,N[/tex]

The average impact force is 12000 newtons.

Highlight two factors which shows that heat from the sun does reach the earth's surface by convection.

Answers

radiation

when the suns radiation fall on the earth and its objects they receive heat energy and hence get heated. Thus the suns heat reaches the earth by. the process of radiation

Absence of medium is the factor which shows that heat from the sun does reach the earth's surface by convection.

The heat of the sun reaches the earth only through radiation because radiation does not require any medium for the transfer of energy but convection and conduction required a medium to transfer heat energy.

We know that there is no medium present in vacuum so convection and conduction are impossible in a vacuum that's why the sun's heat does not reach the earth by conduction or convection.

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Tyson has been assigned to the offensive line as a left guard on his football team which requires him to make explosive movements and push other players body weight in a specific direction. Which sport skill does he demonstrate as his dominant skill based on this position assignment?

Answers

Answer:

The answer is power.

Explanation:

because in the reading it says it's his dominant skill.

and beacuse i got it right on the test.

Answer:

The answer is power.

Explanation:

10. A pitcher in a professional baseball game throws a fastball, giving the baseball
a momentum of 5.83 kg. m/s. Given that the baseball has a mass of 0.145 kg,
what is its speed?

Answers

Answer: 40.2m/sec

Work: v=p/m= 5.83kg/0.145k=40.2cm/sec

How can I rewrite the equation a - b = d using addition?

Answers

Explanation:

A=b+d that is the way to rewrite the equation

The wavelength of a water wave is 6 cm when the frequency is 10 hertz .

1. What is the distance between successive crests of the wave ?
2. What is the speed of propagation ?
3 What is the period of the wave ?

Please show workings.​

Answers

The distance between successive crests (or successive troughs) is defined as the wavelength. The time elapsed between the crossings of two successive crests through a given point is the period of the wave.The Velocity of propagation (Vp) of a cable is the speed at which an electrical signal can propagate through the cable in comparison to the speed of light. For example, in a vacuum, the velocity of propagation would be 100% or 1 (depending on how it is represented).The wave period is the time it takes to complete one cycle. The standard unit of a wave period is in seconds, and it is inversely proportional to the frequency of a wave, which is the number of cycles of waves that occur in one second.

can someone help me please? thank you

Answers

....................

A firework is launched with a force of 700 N and a momentum of 200 kg-m/s. How much time before is explodes?

Answers

Answer:

t = 0.28 seconds

Explanation:

Given that,

Force acting on a firework, F = 700 N

The momentum of the firework, p =200 kg-m/s

We need to find the time before it explodes. Ket the time be t. We know that, the rate of change of momentum is equal to external frce. So,

[tex]F=\dfrac{P}{t}\\\\t=\dfrac{P}{F}\\\\t=\dfrac{200}{700}\\t=0.28\ s[/tex]

So, the required time is equal to 0.28 seconds.

1. Why is the equivalent resistance in a parallel circuit equal to the sum of the reciprocals of the individual resistances, whereas in a series circuit, the equivalent resistance is the sum of the individual resistances? ​

Answers

Answer: Kirchhoff first law: sum of currents coming in branch and leaving it are same.

Explanation: in parallel circuit current is divided between resistors.

In series circuit same current passes through all resistors.


Which statement best summarizes the development of the atomic theory over time?

Answers

Answer:

electrons move around nucleus in specific regions

We have that the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory.

Option B

Generally

The Image shows that in the early 1800 the knowledge of atom was limited and it increased over time and by 1920 it had gone through a 4 stages of modifications to the atomic model

Atoms are solid spheresElectrons are attached to atom surfaceElectrons  move around in the nucleus in a specificRapid motion of electrons in the cloud

Therefore the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory

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Match the choices below to the correct description. Drag the terms on the left to the appropriate blanks on the right. ResetHelp blank − this body wave is a compressional wave. − this body wave is a compressional wave. blank − this body wave is a shear wave. − this body wave is a shear wave. blank − this surface wave moves from side to side. − this surface wave moves from side to side. blank − this surface wave moves up and down. − this surface wave moves up and down.

Answers

Answer: hello the terms are missing but I have provided the answer ( the terms and matched them properly

answer :

P WAVESS WAVESL WAVESR WAVES

Explanation:

This body wave is a compressional wave  : P WAVES

This body wave is a shear wave :  S  WAVES

This surface wave moves from side to side : L WAVES

This surface wave moves up and down. : R WAVES

A body wave is a type of wave that passes through the interior of the earth and they are classified as ; P and S waves while surface waves are seismic waves that travel near the earth's surface

Two resistors, 2.50 Ω and 4.95 Ω, are wired in series to a 12.00 V battery. What is the equivalent resistance of the circuit?

Answers

Answer:

7.45 Ω

Explanation:

From the question given above, the following data were obtained:

Resistor 1 (R₁) = 2.50 Ω

Resistor 2 (R₂) = 4.95 Ω

Voltage (V) = 12 V

Equivalent Resistance (Rₑq) =?

Since the resistors are in series arrangement, the equivalent resistance can be obtained as follow:

Rₑq = R₁ + R₂

Rₑq = 2.5 + 4.95

Rₑq = 7.45 Ω

Therefore, the equivalent resistance is 7.45 Ω

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