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A person's body is producing energy internally due to metabolic processes. If the body loses more energy than metabolic processe

Allushta [10]

To solve this problem it is necessary to apply the concepts related to the Stefan-Boltzman law that is responsible for calculating radioactive energy.

Mathematically this expression can be given as

$P = \sigma Ae\Delta T^4$

Where

A = Surface area of the Object

$\sigma =$ Stefan-Boltzmann constant

e = Emissivity

T = Temperature (Kelvin)

Our values are given as

$A = 1.36m^2$

$\Delta T^4 = T_2^4 -T_1^4 = 307^4-T_1^4$

$\sigma = 5.67*10^{-8} J/(s m^2 K^4)$

$P = 122J/s$

$e = 0.7$

Replacing at our equation and solving to find the temperature 1 we have,

$P = \sigma Ae\Delta T^4$

$P = \sigma Ae (T_2^4 -T_1^4)$

$122 = (5.67*10^{-8})(1.36)(0.7)(307^4-T_1^4)$

$T_1 = 285.272K = 12.122\°C$

Therefore the the temperature of the coldest room in which this person could stand and not experience a drop in body temperature is 12°C

8 0

3 years ago

The same 2000 kg truck formerly traveling at 32 m/s, plows into a

kvasek [131]

Answer: |F| = 1.28 x 10⁵ N

Explanation:

an impulse results in a change of momentum

FΔt = mΔv

F = m(vf - vi)/t

F = 2000(0 - 32) / 0.5

F = -128,000

|F| = 1.28 x 10⁵ N

5 0

3 years ago

A projectile is shot directly away from Earth's surface. Neglect the rotation of the Earth.

Maksim231197 [3]

Answer:

Explanation:

We shall apply law of conservation of mechanical energy for projectile being thrown .

Total energy on the surface = total energy at height h required

a ) At height h , velocity = .351 x ( 2 GM/R x h )

$\frac{-GM}{R} + \frac{m\times(.351\times\sqrt{2GM})^2 }{2R } = \frac{-GMm}{R+h} + 0$

$\frac{-GMm}{R} +\frac{1}{2}\times \frac{-2GMm}{R} \times0.123=\frac{-GMm}{R+h}$

$\frac{0.877GMm}{R} =\frac{-GMm}{R+h}$

h = .14 R

b )

$\frac{-GM}{R} + \frac{m\times(.351\times2GM) }{2R } = \frac{-GMm}{R+h} + 0$

$\frac{-0.649GMm}{R} = \frac{-GMm}{R+h}$

h = .54 R

c ) least initial mechanical energy required at launch if the projectile is to escape Earth

= GMm / R + 1/2 m (2GM/R)

= 0

5 0

3 years ago

Three 15-Î© and two 25-Î© light bulbs and a 24 V battery are connected in a series circuit. What is the current that passes thro

serious [3.7K]

Answer:

I = 0.25 A

Explanation:

Given that,

Three 15 ohms and two 25 ohms light bulbs and a 24 V battery are connected in a series circuit.

In series combination, the equivalent resistance is given by :

$R=R_1+R_2+R_3+....$

So,

$R=15+15+15+25+25\\\\=95\ \Omega$

The current each resistor remains the same in series combination. It can be calculated using Ohm's law i.e.

V = IR

$I=\dfrac{V}{R}\\\\I=\dfrac{24}{95}\\\\I=0.25\ A$

So, the current of 0.25 A passes through each bulb.

5 0

3 years ago

Meghan and Rachel each have bowling balls with the same mass. They both roll them as hard as they can and then measure the speed

svetlana [45]

consider the motion of bowling ball rolled by megan :

v₀ = initial velocity of the ball = 0 m/s

v = final velocity of the ball

a = acceleration of the ball

t = time of travel

using the kinematics equation

v = v₀ + a t

v = 0 + a t

a = v/t eq-1

consider the motion of bowling ball rolled by rachel :

v₀ = initial velocity of the ball = 0 m/s

v' = final velocity of the ball

a' = acceleration of the ball

t = time of travel

using the kinematics equation

v' = v'₀ + a' t

v' = 0 + a' t

a' = v' /t eq-2

dividing eq-1 by eq-2

a/a' = (v/t)/(v'/t)

a/a' = v /v'

Given that : v = v'/2

hence

a/a' = (v'/2) /v'

a/a' = 1/2

ma / ma' = 1/2

F/F' = 1/2

F = F'/2

hence Rachel used twice the force that Meghan did

so correct choice is B)

5 0

3 years ago