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3 years ago

A 60 kg skydiver is falling at a terminal velocity of 50 m/s.

Physics

1 answer:

marishachu [46]3 years ago

5 0

Answer:

The gravitational force is definitely acting downwards towards the ground and this is equal to the weight of the skydiver.

the acceleration a = 7.8 m/s²

Explanation:

Given that :

the mass of the skydiver = 60 kg

Velocity = 50 m/s

Thus; gravitational force is definitely acting downwards towards the ground and this is equal to the weight of the skydiver.

Also; the air resistance is acting upward and the resultant of both forces = mass×acceleration

So;

mg-R = ma

60(9.8) - 120 = 60(a)

588 -120 = 60a

468 = 60a

a = $\frac{468}{60}$

a = 7.8 m/s²

Hence, the acceleration a = 7.8 m/s²

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Explanation:

It is given that,

Focal length of the concave mirror, f = -13.5 cm

Image distance, v = -37.5 cm (in front of mirror)

Let u is the object distance. It can be calculated using the mirror's formula as :

$\dfrac{1}{v}+\dfrac{1}{u}=\dfrac{1}{f}$

$\dfrac{1}{u}=\dfrac{1}{f}-\dfrac{1}{v}$

$\dfrac{1}{u}=\dfrac{1}{(-13.5)}-\dfrac{1}{(-37.5)}$

u = -21.09 cm

The magnification of the mirror is given by :

$m=\dfrac{-v}{u}$

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A beam of light, with a wavelength of 4170 Å, is shined on sodium, which has a work function (binding energy) of 4.41 × 10 –19 J

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Explanation:

Given that,

Wavelength of the light, $\lambda=4170\ A=4170\times 10^{-10}\ m$

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The formula of kinetic energy is given by :

$KE=\dfrac{1}{2}mv^2\\\\v=\sqrt{\dfrac{2KE}{m}} \\\\v=\sqrt{\dfrac{2\times 3.59\times 10^{-20}}{9.1\times 10^{-31}}} \\\\v=2.8\times 10^5\ m/s$

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3 years ago

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Answer:

$0.741\ \text{m/s}^2$

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De las ecuaciones cinemáticas tenemos

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22) A driver traveling at 80 km/h brakes her 2000 kg truck to stop for a red light. How much internal energy is produced

blsea [12.9K]

Answer:

$E=4.9\times 10^5\ J$

Explanation:

Given that,

The speed of a driver, v = 80 km/h = 22.22 m/s

The mass of the truck, m = 2000 kg

We need to find how much internal energy is produced. The internal energy produced by a truck is its kinetic energy and it is given by :

$E=\dfrac{1}{2}mv^2\\\\E=\dfrac{1}{2}\cdot22.22^{2}\cdot2000\\\\E=493728.4\ J$

$E=4.9\times 10^5\ J$

So, $4.9\times 10^5\ J$ of internal energy is produced.

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3 years ago