While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 68 kg person develops a power of 61 W during a race, how fast is the person running

Answers

Answer 1

Answer:

Speed = 2.25 m/s

Explanation:

(Assume a running step is 1.5 m long)

Given the following data;

Energy = 0.6J

Power = 61 Watts

Mass = 68 kg

To find how fast the person running;

First of all, we would determine the total mechanical energy being dissipated by the person.

Total energy = 0.6 * 68

Total energy = 40.8 Joules

Next, we find the time;

Energy = power * time

40.8 = 61 * time

Time = 61/40.8

Time = 1.5 seconds

Finally, to find the speed;

Speed = distance/time

Speed = number of steps * time

Speed = 1.5 * 1.5

Speed = 2.25 m/s


Related Questions

BRAINLY PLS HELP ME!!!


Should the Us government regulate sugar? In once sentence write down what you are preparing to argue or what stance you are going to take. This will help you to create a starting point for your idea

Answers

Answer:

yes

Explanation:

Sugar can cause health problems.

I believe that sugar should be regulated by the government since it causes heath problems. As according to this website heathline.com that up to one third of the population in America is obese. As well as that regulating sugar will greatly help lowering that number, seeing that many food products have tons of sugar in them. By lowering the sugar and regulating it can cause less obesity among the average person in the US. As stated by HeathlyFoodAmerca.org consuming too much sugar can cause increased heath problems as shown, heart disease, diabetes, and teeth decay and this is why I believe that the U.S government should regulate sugar more.

Which of the following elements has the largest atomic radius?
Silicon
Aluminum
Sulfur
Phosphorous

Answers

aluminum has the largest atomic radius

Answer:

francium

Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.

Problem

A charged particle is moving in the presence of uniform magnetic field. The mass of the particle

is m = 10−6 kg its charge is Q = 10−5 C and the magnetic field vector is B~ = (1T, 0, 0). At the

beginning the velocity vector of the particle is ~v0 = (12 m/s, 0, 5 m/s).

a.) How large will the x component of the velocity of the particle be in t = 2 s?

b.) Where will the particle be in t = 3.14 s?

c.) How large will the magnitude of the velocity be in t = 2.5 s?​

Answers

Answer:

Answer is a I checked the work

Given that o.2i+bj+o.4k is a unit vector,what is the value of b?

Answers

Answer:

b = 0.89

Explanation:

The given vector is, [tex]A=0.2i+bj+0.4k[/tex]

A is a unit vector

We need to find the value of b.

For a unit vector, |A| = 1

So,

[tex]0.2^2+b^2+0.4^2=1\\\\0.04+b^2+0.16=1\\\\0.2+b^2=1\\\\b^2=1-0.2\\\\b=0.89[/tex]

So, th value of b is 0.89.

assuming a filament in a 120W light bulb acts like a prefect blackbody, what is the temperature of the hottest portion of the filament if it has a surface area of 6.4×10^_5m^2. The stefan- boltzmann constant is 5.67×10^-8W/(m2.k2) A. 12OOk B. 2400K C. 2100K​

Answers

Answer:

T = 2398 K

Explanation:

To calculate the emission of the light bulb we use the law is Stefan

           P = σ A e T⁴

as they indicate that the filament is a black body, the emissivity is equal to 1 (e = 1)

           T = [tex]\sqrt[4]{\frac{P}{ \sigma A} }[/tex]

    let's calculate

           T =[tex]\sqrt[4]{\frac{120}{5.67 \ 10^{-8} \ 6.4 \ 10^{-5}} }[/tex]

           T = [tex]\sqrt[4]{33.06878 \ 10^{12} }[/tex]

           T = 2,398 10³ K

           T = 2398 K

what is the frequency of a wave related to​

Answers

Answer:

Frequency is the number of complete oscillations or cycles or revolutions made in one second.

What is the friction force on a box that has a mass of 15kg as it slides across the floor. The coefficient of friction of the not very clean floor is 0.25
please explain everything including formula used ​

Answers

Answer:

36.75 N

Explanation:

Applying

F = mgμ................. Equation 1

Where F = Friction force on the box, m = mass of the box, g = acceleration due to gravity of the box, μ = coefficient of static friction

From the question,

Given: m = 15 kg, μ = 0.25

Constant: g = 9.8 m/s²

Substitute these values into equation 1

F = 15(9.8)(0.25)

F = 36.75 N

Hence the friction force on the box is 36.75 N

According to Coulomb's law, if the separation between two particles of the same charge increases four times, the potential energy of the two particles:__________.
a. is one-sixteenth as high as it was before the separation.
b. is four times as high as it was before the distance separation.
c. is one-fourth as high as it was before the separation.
d. does not change.

Answers

Answer:

c.   V = k Q1 * Q2 / R1      potential energy of Q1 and Q2 separated by R

V2 / V1 = (R1 / R2) = 1/4

V2 = V1 / 4

According to Coulomb's law, if the separation between two particles of the same charge increases four times, the potential energy of the two particles is is one-fourth as high as it was before the separation. The correct option is c.

What is Coulomb's law?

Coulomb's law states that the force of attraction or repulsion among both two charged bodies is directly related to the sum of their charges and inversely proportional to the square of the distance between them.

Coulomb force is the attraction or repulsion of particles or objects due to their electric charge. It is also known as electrostatic force or Coulomb interaction.

It denotes the electric force's inverse square dependence. It can also be used to accurately provide relatively simple derivations of Gauss' law for general cases.

Coulomb's law states that if the separation between two particles of the same charge increases four times, the potential energy of the two particles is one-fourth of what it was before the separation.

Thus, the correct option is c.

For more details regarding Coulomb's law, visit:

https://brainly.com/question/506926

#SPJ2

A ball is thrown horizontally at a speed of 24 meters per second from the top of a cliff. If the ball hits the ground 6.0 seconds later, approximately how high is the cliff? ​

Answers

Answer:

144 meters

Explanation:

it takes 6 seconds to hit the ground right and the ball lays off 24 m per second .

so by the time the ball hits the ground 6 seconds passed. so that means the cliff is 6.0×24=144

A constant force moves an object along the line segment from to . Find the work done if the distance is measured in meters and the force in newtons.

Answers

This question is incomplete, the complete question is;

Flag

A constant force F = 6i+8j-6k moves an object along a straight line from point (6, 0, -10) to point (-6, 7, 2).

Find the work done if the distance is measured in meters and the magnitude of the force is measured in newtons.

Answer:

the work done is -88 J

Explanation:

Given the data in the question;

we know that;

Work done = F × S

where constant force F = ( 6i + 8j - 6k )

S = ( -6i + 7j + 2k ) - ( 6i + 0j - 10k )

S = ( (-6i - 6i) + (7j - 0j) + ( 2k - ( -10k) ) )

S = ( -12I + 7j + 12k )

so

Work force = ( 6i + 8j - 6k ) × ( -12I + 7j + 12k )

Work force = ( 6 × -12 ) + ( 8 × 7 ) + ( -6 × 12 )

Work force = -72 + 56 - 72

Work force = -88 J

Therefore, the work done is -88 J

An electric field is given by in units of N/C when is in meters. What is the potential difference from point B at (0,7) m to point A at (7,0) m

Answers

Complete Question

An electric field is given by E= (5x, 0, 0) in units of N/C when x is in meters. What is the potential difference VA - VB from point B at (0,7) m to point A at (7,0) m? V

Answer:

[tex]V_A-V_B=-122.5V[/tex]

Explanation:

From the question we are told that:

Position of point [tex]B=(0,7) m[/tex]

Position of point [tex]A=(7,0) m[/tex]

Generally the equation for pd across the points is mathematically given by

 [tex]V_A-V_B=-\int_0^7(5x)d[/tex]

 [tex]V_A-V_B=-[\frac{5x^2}{2}]_0^7[/tex]

 [tex]V_A-V_B=-[\frac{5(7)^2}{2}][/tex]

 [tex]V_A-V_B=-122.5V[/tex]

A 25 kg box of textbooks rests on a loading ramp that makes an angle α with the horizontal. The coefficient of kinetic friction is 0.25, and the coefficient of static friction is 0.35. As the angle is increased, find the minimum angle at which the box starts to slip.


24.5°


18.5°


21.3°


19.3°

Answers

Up until the moment the box starts to slip, the static friction is maximized with magnitude f, so that by Newton's second law,

• the net force acting on the box parallel to the ramp is

F = mg sin(α) - f = 0

where mg sin(α) is the magnitude of the parallel component of the box's weight; and

• the net force acting perpendicular to the ramp is

F = n - mg cos(α) = 0

where n is the magnitude of the normal force and mg cos(α) is the magnitude of the perpendicular component of weight.

From the second equation we have

n = mg cos(α)

and f = µn = µmg cos(α), where µ is the coefficient of static friction. Substituting these into the first equation gives us

mg sin(α) = µmg cos(α)   ==>   µ = tan(α)   ==>   α = arctan(0.35) ≈ 19.3°

differentiate between step up and step down transformer​

Answers

Answer:

The main difference between the step-up and step-down transformer is that the step-up transformer increases the output voltage, while the step-down transformer reduces the output voltage.

A spring scale hung from the ceiling stretches by 6.1cm when a 2.0kg mass is hung from it. The 2.0kg mass is removed and replaced with a 2.8kg mass.What is the stretch of the spring?

Answers

2.0kg and the mass of sometimes makes it hard 2.8kg

An electric field is produced by the very long, uniformly charged rod drawn above. If the strength of the electric field is E1 at a distance 1 r from the axis of the rod, at what distance from the axis is the field strength 1

Answers

Answer: hello the complete question is attached below

answer :

r2 = 4r1

Explanation:

Electric field strength = F / q

we will assume the rod has an infinite length

For an infinitely charged rod

E ∝ 1/ r

considering two electric fields E1 and E2 at two different locations as described in the question

E1/E2 = r1/r2 ----- ( 2 )

Calculate for r2 when E2 = E1/4

back to equation 2

E1 / (E1/4) = r1 / r2

r2 = 4r1

explain why this is important for life on earth​

Answers

Answer:

THIS is very important.

Explanation:

If the word "this" was never invented, people wouldn't have a way to tell another person what is directly in front of them.

BTW this is a joke.

PLEASE ANSWR 1ST AND I WILL MARK U BRAINLIEST
Two statements are given- one labeled Assertion (A) and the other labeled Reason ®. Select
the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
a. Both A and R are true, and R is correct explanation of the assertion.
b. Both A and R are true, but R is not the correct explanation of the assertion.
c. A is true, but R is false.
d. A is false, but R is true.
Assertion: An object has a negative acceleration.
Reason: The velocity of an object decreases in the same direction.

Answers

Answer:

Where is the R statement?

if p=2i+4j+3k and q=I+5j-2k,find P×q.

Answers

Answer:

[tex]p\times q=-23i+7j+6k[/tex]

Explanation:

We are given that

p=2i+4j+3k

q=i+5j-2k

We have to find pxq

We know that

[tex]p\times q=\begin{vmatrix}  i&j  &k\\  2&4  & 3\\  1& 5 & -2\end{vmatrix}[/tex]

[tex]p\times q=i(-8-15)-j(-4-3)+k(10-4)[/tex]

[tex]p\times q=-23i+7j+6k[/tex]

Hence,[tex]p\times q=-23i+7j+6k[/tex]

You swing a bat and hit a heavy box with a force of 1273 N. The force the box exerts on the bat is Group of answer choices less than 1273 N if the box moves. exactly 1273 N whether or not the box moves. None of the above choices are correct. exactly 1273 N only if the box does not move. greater than 1273 N if the bat bounces back. greater than 1273 N if the box moves.

Answers

Answer:

exactly 1273 N whether or not the box moves.

Explanation:

In the case when the bat is swing and it is hitted to a heavy box having a force of 1273 N so here the force of the box that exert on the box should be accurately 1273 N even if the box is moved or not. As the third law of the newton should be equivalent & the opposite reaction

Therefore as per the given situation, the above represent the answer

calculate the total resistance in the circuit​

Answers

Answer:

The total resistance of a series circuit is equal to the sum of individual resistances. Voltage applied to a series circuit is equal to the sum of the individual voltage drops. The voltage drop across a resistor in a series circuit is directly proportional to the size of the resistor.


If you know the total current and the voltage across the whole circuit, you can find the total resistance using Ohm's Law: R = V / I. For example, a parallel circuit has a voltage of 9 volts and total current of 3 amps. The total resistance RT = 9 volts / 3 amps = 3 Ω.

Spin cycles of washing machines remove water from clothes by producing a large radial acceleration at the rim of the cylindrical tub that holds the water and clothes. Suppose that the diameter of the tub in a typical home washing machine is 50 cm.

Required:
What is the rotation rate, in rev/min, of the tub during the spin cycle if the radial acceleration of points on the tub wall is 3g?

Answers

Answer:

The rate of rotation is 1123.6 rpm.

Explanation:

diameter of tub =50 cm

radius of tub, r = 25 cm = 0.25 m

Acceleration, a = 3 g

The centripetal acceleration is given by

[tex]a = r w^2\\\\3\times 9.8 =0.25 \times w^2\\\\w = 117.6 rad/s\\\\w = 2\pi n \\\\117.6 = 2\times 3.14 \times n\\\\n = 18.73 rps = 1123.6 rpm[/tex]

A swimmer heading directly across a river that is 200 m wide reaches the opposite bank in 6 min 40 s. During this swim, she is swept downstream 480 m. How fast can she swim in still water

Answers

Answer:

The speed of the swimmer in stil water is 0.5 m/s

Explanation:

Given;

total time taken to swim across = 6 mins 40 s = (6 x 60s) + 40 s = 400 s

width of the river, = 200 m

Please find the image attached for explanation.

Find the ratio of the diameter of copper to iron wire, if they have the same resistance per unit length (as they might in household wiring). dCu dFe =

Answers

Answer:

The ratio of diameter of copper wire to the iron wire is 0.42.

Explanation:

length of both the wires is same as L and resistance is R.

resistivity of copper = 1.7 x 10^-8 ohm m

resistivity of iron = 9.7 x 10^-8 ohm m

Let the diameter of copper is d and for iron is d'.

The formula of the resistance is

[tex]R = \rho\times\frac{L}{A}\\\\R = \rho\times\frac{4L}{\pi d^2}.... (1)\\And\\ R = \rho'\times\frac{4L}{\pi d'^2}.... (2)\\\\comparing (1) by (2)\\\\1.7\times10^{-8}\times\frac{4L}{\pi d^2}=9.7\times10^{-8}\times\frac{4L}{\pi d'^2}\\\\d : d' = 0.42[/tex]

jjjjjjjjjjjjalkshadl,wnkdalsssssicj

Answers

Intramolecular Forces:-

An intramolecular force (or primary forces) is any force that binds together the atoms making up a molecule or compound, not to be confused with intermolecular forces, which are the forces present between molecules.

you are given a set of facts regarding a lens : object heigh, and dostance to objects. Given this jnformation, how can you tell if you're dealing with a concave or convex lens

Answers

Answer:

concave curves inward like an hourglass and convex is an outward curve like a football

Explanation:

hope this helps

Help!!
A table is pushed across the floor for a distance of 32 m with a force of 320 N in 150 seconds. How much power was used?
A.70.2W
B.68.3W
C.56.7W
D.49.8W

Answers

Compute the work done on the table:

W = Fd = (320 N) (32 m) = 10,240 J

Divide this by the given time duration to get the power output:

P = W/∆t = (10,240 J) / (150 s) ≈ 63.3 W

An empty 12,954 kg railroad car, traveling at a speed of 28 m/s strikes a partially filled 17,616 kg railroad car moving in the same direction at a speed of 5 m/s. What is the total momentum of the two railroad cars AFTER the collision?

Answers

Answer:

450792 kgm/s

Explanation:

by conservation of momentum,

total momentum AFTER collision = total momentum BEFORE collision

                                                       =mv+m'v'

                                                       =12954×28+17616×5

                                                       =450792 kgm/s

A truck is hauling a 300-kg log out of a ditch using a winch attached to the back of the truck. Knowing the winch applies a constant force of 2850 N and the coefficient of kinetic friction between the ground and the log is 0.45, determine the time for the log to reach a speed of 0.5 m/s

Answers

Answer:

0.1 s

Explanation:

The net force on the log is F - f = ma where F = force due to winch = 2850 N, f = kinetic frictional force = μmg where μ = coefficient of kinetic friction between log and ground = 0.45, m = mass of log = 300 kg and g = acceleration due to gravity = 9.8 m/s² and a = acceleration of log

So F - f = ma

F - μmg = ma

F/m - μg = a

So, substituting the values of the variables into the equation, we have

a = F/m - μg

a = 2850 N/300 kg - 0.45 × 9.8 m/s²

a = 9.5 m/s² - 4.41 m/s²

a = 5.09 m/s²

Since acceleration, a = (v - u)/t where u = initial velocity of log = 0 m/s (since it was a rest before being pulled out of the ditch), v = final velocity of log = 0.5 m/s and t = time taken for the log to reach a speed of 0.5 m/s.

So, making t subject of the formula, we have

t = (v - u)/a

substituting the values of the variables into the equation, we have

t = (v - u)/a

t = (0.5 m/s - 0 m/s)/5.09 m/s²

t = 0.5 m/s ÷ 5.09 m/s²

t = 0.098 s

t ≅ 0.1 s

An electronic voltage is a varying electric current that represents information. True or False​

Answers

Answer:

Explanation:

The word current is never used with voltage. Current, technically, is amperage. Amperage is defined much differently than voltage.

The answer is False.


During the fission reaction shown, how did the target nucleus change ?

Answers

Answer:

A. The target nucleus split into two nuclei, each with fewer nucleons than the original.

Explanation:

Answer: A. The target nucleus split into two nuclei, each with fewer nucleons than the original.

Explanation:

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