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Romashka-Z-Leto [24]
3 years ago
10

A 60-kg runner raises his center of mass approximately 0.5 m with each step. Although his leg muscles act as a spring, recapturi

ng the energy each time his feet touch down, there’s an average 10% loss with each compression. What must the runner’s additional power output be to account for just this loss, if he averages 0.8 s per stride?
Physics
1 answer:
Darina [25.2K]3 years ago
5 0

Answer: P = 36.75W

The additional power needed to account for the loss is 36.75W.

Explanation:

Given;

Mass of the runner m= 60 kg

Height of the centre of gravity h= 0.5m

Acceleration due to gravity g= 9.8m/s

The potential energy of the body for each step is;

P.E = mgh

P.E = 60 × 9.8 × 0.5

PE = 294J

Since the average loss per compression on the leg is 10%.

Energy loss = 10% (P.E)

E = 10% of 294J

E = 29.4J

To calculate the runner's additional power

given that time per stride is = 0.8s

Power P = Energy/time

P = E/t

P = 29.4J/0.8s

P = 36.75W

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igor_vitrenko [27]

Answer:

  1) Option D

  2) Option D

  3) Option C

Explanation:

1) Kinetic energy =\frac{1}{2} mv^2

    m = 500 kg

    v = 10 m/s

   Kinetic energy =\frac{1}{2} *500*10^2=25000 J

   Option D is the correct answer.

2) Potential energy = mgh

   m = 25 kg

    g = 10 m/s²

    h = 42 m

     Potential energy = 25 * 10 * 42 = 10500 J

   Option D is the correct answer.

3) Thermal equilibrium means no heat flow from each other two systems, that is achieved when both systems have same temperature.

  Option C is the correct answer.

7 0
3 years ago
Which be behavior of light makes it possible for you to see a spectrum of colors in a spray of water on a sunny day?
Vikentia [17]
B. Reflection (I just googled it )
3 0
3 years ago
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Two charged objects have a repulsive force of 0.050 N. If the charge of both of the objects is doubled, then what is the new for
grandymaker [24]

Answer: 4 times grease

Explanation: Force F= C · q1·q2/r². C = Coulomb's constant.

If charges double you have 2q1 and 2q2.

7 0
3 years ago
The left end of a long glass rod 8.00 cm in diameter and with an index of refraction of 1.60 is ground and polished to a convex
lesya692 [45]

Answer:

A) 0.1477

B) 0.65388 mm

C) object is inverted

Explanation:

The formula for object - image relationships for spherical reflecting surface is given as;

n1/s + n2/s' = = (n2 - n1)/R

Where;

n1 & n2 are the Refractive index of both surfaces

s is the object distance from the vertex of the spherical surface

s' is the image distance from the vertex of the spherical surface

R is the radius of the spherical surface

We are given;

index of refraction of glass; n2 = 1.60

s = 24 cm = 0.24 m

R = 4 cm = 0.04 m

index of refraction of air has a standard value of 1. Thus; n1 = 1

a) So, making s' the subject from the initial equation, we have;

s' = n2/[((n2 - n1)/R) - n1/s]

Plugging in the relevant values, we have;

s' = 1.6/[((1.6 - 1)/0.04) - 1/0.24]

s' = 0.1477

b) The formula for lateral magnification of spherical reflecting surfaces is;

m = -(n1 × s')/(n2 × s) = y'/y

Where;

m is the magnification

n1, n2, s & s' remain as earlier explained

y is the height of the object

y' is the height of the image

Making y' the subject, we have;

y' = -(n1 × s' × y)/(n2 × s)

We are given y = 1.7 mm = 0.0017 m and all the other terms remain as before.

Thus;

y' = -(1 × 0.1477 × 0.0017)/(1.6 × 0.24)

y' = - 0.00065388021 m = -0.65388 mm

C) since y' is negative and y is positive therefore, m = y'/y would result in a negative value.

Now, in object - image relationships for spherical reflecting surface, when magnification is positive, it means the object is erect and when magnification is negative, it means the object is inverted.

Thus, the object is inverted since m is negative.

6 0
3 years ago
If the pendulum is taken into the orbiting space station what will happen to the bob? if the pendulum is taken into the orbiting
mezya [45]
Check the attached file for the answer.

3 0
4 years ago
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