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3 years ago

13

The world record for the hundred meter dash is 9.77 s. what is the corresponding average speed in units of m/s, km/h, ft/s, and

mi/h?

1 answer:

kotegsom [21]3 years ago

8 0

The answer is

in (m/s) : 100m / 9.77s = 10.2354 m/s

in (km/h) : (100/1000 or 0.1) km / (9.77/3600 or 0.002714) h = 36.84 km/h

in (ft/s) : 33.5807 ft / s

in mi / h : 22.8959 mi / h

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Two positive charges q1 = q2 = 2.0 μC are located at x = 0, y = 0.30 m and x = 0, y = -0.30 m, respectively. Third point charge

Wittaler [7]

Answer:

F = 0.111015 N

Explanation:

For this exercise the force is given by Coulomb's law

F = k q₁q₂ / r₂₁²

we calculate the electric force of the other two particles on the charge q1

Charges q₁ and q₂

the distance between them is

r₁₂ = y₁ -y₂

r₁₂ = 0.30 + 0.30

r₁₂ = 0.60 m

let's calculate

F₁₂ = 9 10⁹ 2 10⁻⁶ 2 10⁻⁶ / 0.60 2

F₁₂ = 1 10⁻¹ N

directed towards the positive side of the y-axis

Charges 1 and 3

Let's find the distance using the Pythagorean Theorem

r₁₃ = RA [(0.40-0) 2 + (0-0.30) 2]

r₁₃ = 0.50 m

F₁₃ = 9 10⁹ 2 10⁻⁶ 4 10⁻⁶ / 0.50²

F₁₃ = 1.697 10⁻² N

The direction of this force is on the line that joins the two charges (1 and 3), let's use trigonometry to find the components of this force

tan θ = y / x

θ = tan⁻¹ y / x

θ = tan⁻¹ 0.3 / 0.4

tea = 36.87º

The angle from the positive side of the x-axis is

θ ’= 180 - θ

θ ’= 180 - 36.87

θ ’= 143.13º

sin143.13 = F_13y / F₁₃

F_13y = F₁₃ sin 143.13

F{13y} = 1.697 10⁻² sin 143.13

F_13y = 1.0183 10⁻² N

cos 143.13 = F_13x / F₁₃

F₁₃ₓ = F₁₃ cos 143.13

F₁₃ₓ = 1.697 10⁻² cos 143.13

F₁₃ₓ = -1.357 10-2 N

Now we can find the components of the resultant force

Fx = F13x + F12x

Fx = -1,357 10-2 +0

Fx = -1.357 10-2 N

Fy = F13y + F12y

Fy = 1.0183 10-2 + 1 10-1

Fy = 0.110183 N

We use the Pythagorean theorem to find the modulus

F = Ra (Fx2 + Fy2)

F = RA [(1.357 10-2) 2 + 0.110183 2]

F = 0.111015 N

Let's use trigonometry for the angles

tan tea = Fy / Fx

tea = tan-1 (0.110183 / -0.01357)

tea = 1,448 rad

to find the angle about the positive side of the + x axis

tea '= pi - 1,448

Tea = 1.6936 rad

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3 years ago

Which process can transfer energy to a solid metal block

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Eneregy is the ability to to do work it takes work to heat someone heat is energy put the solid metal block in a campfire and heat it up tada wait, we need the options, nevermind

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3 years ago

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A particle's trajectory is described by x = (0.5t^3-2t^2) meters and y = (0.5t^2-2t), where time is in seconds. What is the part

mestny [16]

Differentiate the components of position to get the corresponding components of velocity :

$v_x = \dfrac{\mathrm dx}{\mathrm dt} = \left(1.5\dfrac{\rm m}{\mathrm s^3}\right) t^2 - \left(4\dfrac{\rm m}{\mathrm s^2}\right)t$

$v_y = \dfrac{\mathrm dy}{\mathrm dt} = \left(1\dfrac{\rm m}{\mathrm s^2}\right)t-2\dfrac{\rm m}{\rm s}$

At <em>t</em> = 5.0 s, the particle has velocity

$v_x = \left(1.5\dfrac{\rm m}{\mathrm s^3}\right) (5.0\,\mathrm s)^2 - \left(4\dfrac{\rm m}{\mathrm s^2}\right)(5.0\,\mathrm s) = 17.5\dfrac{\rm m}{\rm s}$

$v_y = \left(1\dfrac{\rm m}{\mathrm s^2}\right)(5.0\,\mathrm s)-2\dfrac{\rm m}{\rm s} = 3.0\dfrac{\rm m}{\rm s}$

The speed at this time is the magnitude of the velocity :

$\sqrt{{v_x}^2 + {v_y}^2} \approx \boxed{17.8\dfrac{\rm m}{\rm s}}$

The direction of motion at this time is the angle $\theta$ that the velocity vector makes with the positive <em>x</em>-axis, such that

$\tan(\theta) = \dfrac{3.0\frac{\rm m}{\rm s}}{17.5\frac{\rm m}{\rm s}} \implies \theta = \tan^{-1}\left(\dfrac{3.0}{17.5}\right) \approx \boxed{9.73^\circ}$

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2 years ago

A friend asks you how much pressure is in your car tires. You know that the tire manufacturer recommends 30 psi, but it’s been a

Ghella [55]

Answer: Wallahi i don't know

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3 years ago

The c-cl bond dissociation energy in cf3cl is 339 kj/mol. What is the maximum wavelength of photons that can rupture this bond?

ruslelena [56]

Answer:

3.53*10^{-7} m

Explanation:

Photon that can rupture the bonds are those with the energy of the bond dissociation energy. If we want to know the energy for each molecule we have to take into account that:

$1mol=6.022*10^{23}molecule$

Hence, we have

$E_d=339\frac{10^{3}J}{mol}*\frac{1mol}{6-022*10^{23}molecules}=5.62*10^{-19}J/molecule$

but the energy is also:

$E_d=h\nu =\frac{hc}{\lambda}\\\\\lambda=\frac{hc}{E_d}$

where h is the Planck's constant and c is the speed of ligth. By replacing we obtain:

$\lambda=\frac{(6.62*10^{-34}Js)(3*10^{8}m/s)}{5.62*10^{-19}J}=3.53*10^{-7}m$

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2 years ago

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