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2 years ago

A sprinter starts from rest and runs with constant acceleration to a top speed of 12m/s in 4.0 seconds.

Physics

1 answer:

bagirrra123 [75]2 years ago

4 0

Answer:

a = 3,0 m/s²

Explanation:

En este ejercicio se pide calcular la aceleracion del cuerpo, usemos las ecuaciones de cinematica en una dimensión.

v= v₀ + a t

como el corredor parte del reposo si velocidad inicial es cero

v = at

a = v/t

calculemos

a = 12 /4,0

a = 3,0 m/s²

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10 points

grandymaker [24]

The answer is B tell me if I am wrong.

6 0

2 years ago

The kinetic energy of a proton and that of an a-particle are 4 eV and 1 eV,

madam [21]

Answer:

(b) 1:1

Explanation:

1. Formulae:

E = hf

E = h.v/λ

λ = h/(mv)

E = (1/2)mv²

Where:

E = kinetic energy of the particle
λ = de-Broglie wavelength
m = mass of the particle
v = speed of the particle
h = Planck constant

2. Reasoning

An alha particle contains 2 neutrons and 2 protons, thus its mass number is 4.

A proton has mass number 1.

Thus, the relative masses of an alpha particle and a proton are:

$\dfrac{m_\alpha}{m_p}=4$

For the kinetic energies you find:

$\dfrac{E_\alpha}{E_p}=\dfrac{m_\alpha \times v_\alpha^2}{m_p\times v_p^2}$

$\dfrac{1eV}{4eV}=\dfrac{4\times v_\alpha^2}{1\times v_p^2}\\\\\\\dfrac{v_p^2}{v_\alpha^2}=16\\\\\\\dfrac{v_p}{v_\alpha}=4$

Thus:

$\dfrac{m_\alpha}{m_p}=4=\dfrac{v_p}{v__\alpha}$

$m_\alpha v_\alpha=m_pv_p$

From de-Broglie equation, λ = h/(mv)

$\dfrac{\lambda_p}{\lambda_\alpha}=\dfrac{m_\lambda v_\lambda}{m_pv_p}=\dfrac{1}{1}=1:1$

5 0

3 years ago

As a result of nuclear fusion, the sun produces what 2 types of energy ??

ELEN [110]

Answer:

heat energy and nuclear energy

Explanation:

as a resukt of nuclear fusion, the sun produces two types of energy.

1. heat energy

2. nuclear energy

3 0

2 years ago

A vw beetle goes from 0 to 60 mi/h with an acceleration of 2.35 m/s^2.

Vlad1618 [11]

Part a.
u = 0, the initial velocity
v = 60 mi/h, the final velocity
a = 2.35 m/s², the acceleration.

Note that
1 m = 1609.34 m.
Therefore
v = (60 mi/h)*(1609.34 m/mi)*(1/3600 h/s) = 26.822 m/s
Use the formula
v = u + at
(26.822 m/s) = (2.35 m/s²)*(t s)
t = 26.822/2.35 = 11.4 s

Answer: 11.4 s

Part b.
We already determined that v = 60 mi/h = 26.822 m/s.
t = 0.6 s
Therefore
(26.822 m/s) = (a m/s²)*(0.6 s)
a = 26.822/0.6 = 44.7 m/s²

Answer: 44.7 m/s²

6 0

2 years ago

For a given wave if the frequency doubles the wave length?

pav-90 [236]

For a given wave in a given medium, if the frequency doubles,
the wavelength becomes 50% shorter.

That is, it becomes half as long as it was originally.

5 0

2 years ago