1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Natalka [10]
3 years ago
9

Sprinters push off from the ball of their foot, then bend their knee to bring their foot up close to the body as they swing thei

r leg forward for the next stride. Why is this an effective strategy for running fast?
Physics
1 answer:
Nataliya [291]3 years ago
7 0

There are two interchangeable concepts that can be applied to this theory. The first one is the moment of Inertia and the second the perioricity. When the runners put their leg forward they reduce their moment of inertia allowing their center of mass to maintain the speed they carry and not waste energy. In this way when they swing, the leg begins to act as a kind of pendulum, and remember that the pendulum is directly proportional to the length, that is,

T = 2 \pi \sqrt {l / g}

In this way, by bringing their legs closer they reduce the distance and make the period shorter.

You might be interested in
Emilio tries to jump to a nearby dock from a canoe that is floating in the water.Instead of landing on the dock, he falls into t
kow [346]
The reaction of him pushing off a floating object pushes it away causing him to lose power and balance
7 0
3 years ago
The big bang theory has finally answered one of the biggest questions of science—the origin of the universe.
ss7ja [257]

Answer:

False

Explanation:

According to the big bang theory, matter was an infinitely small and very high density point which at one point exploded and expanded in all directions, creating what we know as our Universe, which also includes space and time . This happened about 13.8 billion years ago. Theoretical physicists have managed to reconstruct this chronology of events from 1/100 of a second after the Big Bang. After the explosion, while the Universe expanded, it cooled sufficiently and the first subatomic particles were formed: Electrons, Positrons, Mesons, Barions, Neutrinos, Photons among others. Today more than 90 particles are known. This theory solves many unknowns and is very well received by the scientific community, however there is still much to solve, for example, one of the great unsolved scientific problems in the expanding Universe model is whether the Universe is open or closed.

An attempt to solve this problem is to determine if the average density of matter in the Universe is greater than the critical value in Friedmann's model. The mass of a galaxy can be measured by observing the movement of its stars; multiplying the mass of each galaxy by the number of galaxies, it is seen that the density is only 5 to 10% of the critical value.

6 0
3 years ago
• Usain Bolt can run at 10 m/s. If he runs for about 20 seconds, how far around the race track did he go?
yanalaym [24]

Answer:

200metters

Explanation:

because in one second hes going 10 metter in 20 second he will go 20×10=200

4 0
3 years ago
The displacement of a 500 g mass, undergoing simple harmonic motion, is defined by the function :
Delicious77 [7]

The maximum kinetic energy, maximum potential energy and the maximum mechanical energy are equal to 7.56J.

<h3>What is simple harmonic motion?</h3>

Simple harmonic motion, in physics, repetitive movement back and forth through an equilibrium, or central, position, so that the maximum displacement on one side of this position is equal to the maximum displacement on the other side.

Simple Harmonic Motion

The given equation of the simple harmonic motion is

x=3.5 sin (\frac{\pi }{2t} + \frac{5\pi }{4} )

Data;

ω = π/2

k = 1.254N/m

Solving this

\frac{dx}{dt} = -3.5 X \frac{\pi }{2} cos (\frac{x\pi t}{2}+\frac{5\pi }{4}  )

Let's calculate the maximum velocity.

V_{m} =\frac{3.5\pi }{2}

This is only possible when cos θ = -1

The maximum kinetic energy is

K_m =\frac{1}{2} mv^2 = \frac{1}{2} X \frac{500}{1000} X \frac{7^2\pi ^2}^{4} ^2

w^2 = \frac{k}{m} \\k = w^2m\\k = \frac{\pi ^2}{4} X \frac{500}{1000} \\k =1.254 N/m

Using the value of spring constant, we can find the maximum potential energy.

P.E =\frac{1}{2} k x^2\\P.E =\frac{1}{2} X 1.234 X 3.5^2 \\P.E = 7.56 J

The maximum potential energy is 7.56J

The maximum mechanical energy is equal to the sum of maximum potential energy and the maximum kinetic energy.

ME = K.E + P.E

ME = 7.56J

From the calculations above, the maximum kinetic energy, maximum potential energy and the maximum mechanical energy are equal to 7.56J.

Learn more on simple harmonic motion here;

brainly.com/question/15556430

#SPJ1

8 0
2 years ago
When monochromatic light illuminates a grating with 7000 lines per centimeter, its second order maximum is at 62.4°. what is the
zhannawk [14.2K]

When red light illuminates a grating with 7000 lines per centimeter, its second maximum is at 62.4°. What is the wavelength of this light?

ans: 633nm

6 0
4 years ago
Read 2 more answers
Other questions:
  • Which characteristics can be used to differentiate star systems? Check all that apply.
    13·2 answers
  • Compare and contrast an electric discharge with an electric current
    12·1 answer
  • By which method does the following move into the cell: movement of oxygen, carbon dioxide, and other small uncharged molecules a
    9·1 answer
  • How is Uranus colder than Neptune
    8·1 answer
  • Originally 21 acts were tentatively scheduled to perform at the arena; only 10 have been booked. What is the shortfall if the ot
    5·1 answer
  • 9<br>How can you prove that air has weight​
    12·2 answers
  • Desi and Consuela are arguing about how to spend the tax refund they received. He says they should get the car fixed; she says t
    14·1 answer
  • A 14 kilogram beam is hinged at one end. A 6.0-kilogram triangular object and a 7.5-kilogram capital I-shaped object are placed
    8·1 answer
  • What is the current flowing through a 10 resistor in a parallel circuit with a 120 V potential difference across it?
    13·2 answers
  • Un objeto que tiene como masa 80 kg acelera a razón de 10 m/s2 ¿que fuerza lo impulzo
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!