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3 years ago

How long does it take for a bicycle traveling 7.0 m/s to come to a stop if the

Physics

2 answers:

Olin [163]3 years ago

7 0

B: 10.5s pc.3.5sbdnshd habsbdjebs

marishachu [46]3 years ago

4 0

initial velocity=u=7m/s
Final velocity=v=0m/s
Acceleration=a=-3.5m/s^2

$\\ \rm\Rrightarrow v=u+at$

$\\ \rm\Rrightarrow t=\dfrac{v-u}{a}$

$\\ \rm\Rrightarrow t=\dfrac{0-7}{-3.5}$

$\\ \rm\Rrightarrow t=\dfrac{-7}{-3.5}$

$\\ \rm\Rrightarrow t=2s$

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A frequently quoted rule of thumb in aircraft design is that wings should produce about 1000 N of lift per square meter of wing.

svetlana [45]

Answer:

v₂ = 63.62 m / s

Explanation:

For this exercise in fluid mechanics we will use Bernoulli's equation

P₁ + ρ g v₁² + ρ g y₁ = P₂ + ρ g v₂² + ρ g y₂

where the subscript 1 refers to the inside of the wing and the subscript 2 to the top of the wing.

We will assume that the distance between the two parts is small, so y₁ = y₂

P₁-P₂ = ρ g (v₂² - v₁²)

pressure is defined by

P = F / A

we substitute

ΔF / A = ρ g (v₂² - v₁²)

v₂² = $\frac{\Delta F}{A \ \rho \ g} + v_1^2$

suppose that the area of the wing is A = 1 m²

we substitute

v₂² = $\frac{1000}{1 \ 1.29 \ 9.8} + 63^2$

v₂² = 79.10 + 3969

v₂ = √4048.1

v₂ = 63.62 m / s

7 0

3 years ago

If ?h°rxn and ?s°rxn are both negative values, what drives the spontaneous reaction and in what direction at standard conditions

irakobra [83]

The release of free energy drives the spontaneous reaction.

Spontaneity can be <span>determined using the change in </span>Gibbs free energy (the thermodynamic potencial):

delta G=delta H – T*delta S

where delta H is the enthalpy and delta S is the entropy.

The direction (the sign) of delta G depends of the changes of enthalpy and entropy. If delta G is negative then the process is spontaneous.

In our case, both delta H and delta S are negative values, the process as said is spontaneous which means that it may proceed in the forward direction.

6 0

3 years ago

A photon of wavelength 7.33 pm scatters at an angle of 157° from an initially stationary, unbound electron. What is the de Brogl

Ann [662]

Answer:

4.63 p.m.

Explanation:

The problem given here can be solved by the Compton effect which is expressed as

$\lambda^{'}-\lambda=\frac{h}{m_e c}(1-cos\theta)$

here, $\lambda$ is the initial photon wavelength, $\lambda^{'}$ is the scattered photon wavelength, h is he Planck's constant, $m_e$ is the free electron mass, c is the velocity of light, $\theta$ is the angle of scattering.

Given that, the scattering angle is, $\theta=157^{\circ}$

Putting the respective values, we get

$\lambda^{'}-\lambda=\frac{6.626\times 10^{-34} }{9.11\times 10^{-31}\times 3\times 10^{8} } (1-cos157^\circ ) m\\\lambda^{'}-\lambda=2.42\times 10^{-12} (1-cos157^\circ ) m\\\lambda^{'}-\lambda=2.42(1-cos157^\circ ) p.m.$

Therfore,

$\lambda^{'}-\lambda=4.64 p.m.$

Here, the photon's incident wavelength is $\lamda=7.33pm$

So,

$\lambda^{'}=7.33+4.64=11.97 p.m$

From the conservation of momentum,

$\vec{P_\lambda}=\vec{P_{\lambda^{'}}}+\vec{P_e}$

here, $\vec{P_\lambda}$ is the initial photon momentum, $\vec{P_{\lambda^{'}}}$ is the final photon momentum and $\vec{P_e}$ is the scattered electron momentum.

Expanding the vector sum, we get

$P^2_{e}=P^2_{\lambda}+P^2_{\lambda^{'}}-2P_\lambda P_{\lambda^{'}}cos\theta$

Now expressing the momentum in terms of De-Broglie wavelength

$P=h/\lambda$ and putting it in the above equation we get,

$\lambda_{e}=\frac{\lambda \lambda^{'}}{\sqrt{\lambda^{2}+\lambda^{2}_{'}-2\lambda \lambda^{'} cos\theta}}$

Therfore,

$\lambda_{e}=\frac{7.33\times 11.97}{\sqrt{7.33^{2}+11.97^{2}-2\times 7.33\times 11.97\times cos157^\circ }} p.m.\\\lambda_{e}=\frac{87.7401}{18.935} = 4.63 p.m.$

This is the de Broglie wavelength of the electron after scattering.

8 0

3 years ago

The conductors that carry the current to electrical devices and ? equipment are the heart of all electrical systems. There are a

Aleksandr [31]

Answer:

Utilization, effects

Explanation:

The conductors that carry the current to electrical devices and utilization equipment are the heart of all electrical systems. There are associated effects whenever current flows through a conductor.

7 0

3 years ago

Which of these accurately describes the products of a reaction?

stiv31 [10]

The one that accurately describes the products of a reaction is : B. new substances that are present at the end of a reaction
For example the process of photosynthesis transform CO2 and other nutrients into O2 and H2O

hope this helps

3 0

3 years ago

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