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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.

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Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below. Overl
olga55 [171]

Answer:

A). A few of the positive particles aimed at a gold foil seemed to bounce back off of the thin metallic foil.

Explanation:

Scientists decided to change the model of the atom when they discovered new evidence that showed 'few of the positive particles aimed at a gold foil seemed to bounce back off of the thin metallic foil.' On this ground, <u>Rutherford concluded that atom is mostly made up of empty space and thus, he proposed a nucleus model of atom in which the atom comprises of the tiny and positively charged nucleus is surrounded by electrons with a negative charge</u>. Thus, <u>option A</u> is the correct answer.

8 0
3 years ago
Read 2 more answers
g A box having mass 0,5kg is placed in front of a 20 cm compressed spring. When the spring released, box having mass m1, collide
vagabundo [1.1K]

Answer:Expression given below

Explanation:

Given mass of spring\left ( m_1\right )=0.5 kg

Compression in the spring\left ( x\right )=20 cm

Let the spring constant be K

Using Energy conservation

potential energy stored in spring =Kinetic energy of Block\left ( m_1\right )

\frac{1}{2}Kx^2=\frac{1}{2}m_1v^2

v=x\sqrt{\frac{k}{m_1}}

now conserving momentum

m_1v=\left ( m_1+m_2\right )v_0

v_0=\frac{m_1}{m_1+m_2}v

where v_0 is the final velocity

3 0
4 years ago
Two large, plastic tubs were filled with soil The soil was shaped to create a mound in each tub. The starting height of each mou
shutvik [7]

Answer:

b

Explanation:

6 0
2 years ago
A flat coil having 160 turns, each with an area of 0.20 m 2, is placed with the plane of its area perpendicular to a magnetic fi
S_A_V [24]

Answer:

10.2 Watt

Explanation:

N  = number of turns in flat coil = 160

A  = area = 0.20 m²

B₀= initial magnetic field = 0.40 T

B  = final magnetic field = - 0.40 T

Change in magnetic field is given as

ΔB = B - B₀ = - 0.40 - 0.40 = - 0.80 T

t  = time taken for the magnetic field to change = 2.0 s

Induced emf is given as

E = \frac{- N A \Delta B}{t}

E = \frac{- (160) (0.20) (- 0.80)}{2}

E = 12.8 volts

R = Resistance of the coil = 16 Ω

Power is given as

P = \frac{E^{2}}{R}

P = \frac{(12.8)^{2}}{16}

P = 10.2 Watt

6 0
3 years ago
Which of these would be best explained by the Doppler effect? A) The change in frequency as you shorten a guitar string. B) The
Lady_Fox [76]

B)

Doppler effect is about the apparent change in frequency. The change in pitch heard as an ambulance approaches you is an example of this

4 0
3 years ago
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