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2 years ago

While eating lunch high up in a skyscraper, two construction workers calculate their gravitational potential

Physics

1 answer:

Maurinko [17]2 years ago

8 0

Answer:

The mass of the other worker is 45 kg

Explanation:

The given parameters are;

The gravitational potential energy of one construction worker = The gravitational potential energy of the other construction worker

The mass of the lighter construction worker, m₁ = 90 kg

The height level of the lighter construction worker's location = h₁

The height level of the other construction worker's location = h₂ = 2·h₁

The gravitational potential energy, P.E., is given as follows;

P.E. = m·g·h

Where;

m = The mass of the object at height

g = The acceleration due to gravity

h = The height at which is located

Let P.E.₁ represent the gravitational potential energy of one construction worker and let P.E.₂ represent the gravitational potential energy of the other construction worker

We have;

P.E.₁ = P.E.₂

Therefore;

m₁·g·h₁ = m₂·g·h₂

h₂ = 2·h₁

We have;

m₁·g·h₁ = m₂·g·2·h₁

m₁ = 2·m₂

90 kg = 2 × m₂

m₂ = (90 kg)/2 = 45 kg

The mass of the other construction worker is 45 kg.

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... find length
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ma = mgsin(10) or a = gsin(10)
a (along the incline)= gsin(10) = 10sin(10) = 1.74
v^2 = u^2 + 2as
15^2 = 3^2 + 2(1.74)s
s = 62.06 m

(way 2) using conservation of energy
energy (KE+PE) on top = energy at bottom
0.5m3^2 + mgh = 0.5m15^2 +0
h (height of incline) = (112.5 - 4.5)/10 = 19.8 m
length of incline = h/sin(10) = 62.2 m ; trigonometry

... find time
s = (u+v)t/2
t = 2s/(u+v) = 2(62.2)/(3+15) = 6.91 s

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3 years ago

A ray of yellow light (f = 5.09 × 1014hz) travels at a speed of 2.04 × 108meters per second in

denis23 [38]

Velocity = fλ

where f is frequency in Hz, and λ is wavelength in meters.

2.04 * 10⁸ m/s = 5.09 * 10¹⁴ Hz * λ

(2.04 * 10⁸ m/s) / (5.09 * 10¹⁴ Hz ) = λ

4.007*10⁻⁷ m = λ

The wavelength of the yellow light = 4.007*10⁻⁷ m

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3 years ago

Bob is moving at 0.967c with respect to Alice. At the exact instant he passes Alice, she fires a very short laser pulse in the s

yulyashka [42]

Explanation:

Speed of Bob, v = 0.967 c

At the exact instant he passes Alice, she fires a very short laser pulse in the same direction Bob is moving.

(a) We need to find the distance measured by Alice between Bob and the laser pulse. It is given by :

$d=ct-vt$

$d=t(c-v)$

$d=5.59\times (c-0.967c)$

$d=5.53\times 10^7\ meters$

(b) Distance measured by Bob between himself and the laser pulse is given by :

$d_B=ct$

$d_B=3\times 10^8\times 5.59$

$d_B=6.67\times 10^9\ meters$

Hence, this is the required solution.

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3 years ago

The mass of the Earth is 6 × 1024 kg, the mass of the Moon is 7 × 1022 kg, and the center-to-center distance is 4 × 108 m. How f

Karolina [17]

Answer:

The center of mass of the Earth–Moon system is 4.613 × 10⁶ m from center of the Earth.

Explanation:

Let the reference point be the center of the Earth

$X_{Cm = \frac{M_eX_e +M_mX_m}{M_e+M_m}$

Where;

Xcm is the distance from center of the Earth =?

Me is the mass of the Earth = 6 × 10²⁴ kg

Xe is the center mass of the Earth = 0

Mm is the mass of the moon = 7 × 10²² kg

Xm is the center mass of the moon = 4 × 10⁸ m

$X_{Cm = \frac{M_eX_e +M_mX_m}{M_e+M_m} = \frac{M_e(0) +M_mX_m}{M_e+M_m} = \frac{ M_mX_m}{M_e+M_m}}\\\\X_C_m = \frac{7 X 10^{22}*4X10^8}{6X10^{24}+7X10^{22}} =\frac{28 X10^{30}}{607X10^{22}}\\\\ X_C_m = 4.613 X10^6 m$

Therefore, the center of mass of the Earth–Moon system is 4.613 × 10⁶ m from center of the Earth.

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3 years ago

If 1 gallon of a liquid weighs 4 pounds how much would one ounce weight (keep in mind that liquid ounces are different than weig

Bas_tet [7]

Answer:

64 ounces

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1 gallon = 4 pounds

1 pound = 16 ounces weight

So,

4 pounds = 16 × 4 = 64 ounces weight

So, 1 gallon is equal to 64 ounces weight.

1 gallon = 128 fluid ounces.

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3 years ago