A jet has amass of 40,000 kg. The thrust for each of the four engines is 20,000 N. What is the jet's acceleration?

A policeman is chasing a criminal across a rooftop at 10 m/s. He decides to jump to the next building which is 2 meters across f

Alexus [3.1K]

At 10 m/s, it will take
(2 m)/(10 m/s) = 0.2 s
to bridge the gap.

_____
However, it will take an additional 0.514 seconds (0.714 s total) for the policeman to land on the building below. The answer depends on the meaning of the question.

3 0

2 years ago

Two 60 cm parallel disks are separated by 40 cm and are aligned directly on top of each other. Both disks are black surfaces wit

Crazy boy [7]

Answer:

775.48 W

Explanation:

given,

diameter of disk = 0.6 cm

length of the disk = 0.4 m

T₁ = 450 K T₂ = 450 K T₃ = 300 K

$\dfrac{d}{r_1}=\dfrac{0.4}{0.3}$ = 1.33

now,

the value of view factor (F₁₂)corresponding to 1.33

F₁₂ = 0.265

F₁₃ = 1 - 0.265 = 0.735

now,

net rate of radiation heat transfer from the disk to the environment:

$=\dot{Q_{1-3}+Q_{2-3}} = 2 \dot{Q_{1-3}}$

= 2 F₁₃ A₁ σ (T₁⁴ - T₃⁴)

= 2 x 0.735 x π x (0.3)² x (5.67 x 10⁻⁸ W/m²) (450⁴ - 300⁴)

= 775.48 W

Net radiation heat transfer from the disks to the environment = 775.48 W

3 0

3 years ago

Calculate the minimum average power output necessary for a person to run up a 12.0 m long hillside, which is inclined at 25.0° a

Viktor [21]

Answer:

Power, P = 924.15 watts

Explanation:

Given that,

Length of the ramp, l = 12 m

Mass of the person, m = 55.8 kg

Angle between the inclined plane and the horizontal, $\theta=25^{\circ}$

Time, t = 3 s

Let h is the height of the hill from the horizontal,

$h=l\ sin\theta$

$h=12\times \ sin(25)$

h = 5.07 m

Let P is the power output necessary for a person to run up long hill side as :

$P=\dfrac{E}{t}$

$P=\dfrac{mgh}{t}$

$P=\dfrac{55.8\times 9.8\times 5.07}{3}$

P = 924.15 watts

So, the minimum average power output necessary for a person to run up is 924.15 watts. Hence, this is the required solution.

3 0

2 years ago

Sometimes you can see a faint reflection in the surface of a shiny plate or cup.Why ?

bazaltina [42]

Answer:

The degree of reflection whether faint or bright you see on the surface of an object is an indication that light particles had hit the surface. Since light is a wave and as part of its characteristics can get reflected. However, the amount of light reflected by a surface is dependent on the smoothness of the surface which can be shiny or dull, it can also be dependent on the nature of the surface which can be glass, water, and so on. So, from the question, you can see a faint reflection on the surface of a shiny plate or cup because of the smoothness of the surface which reflects the lights that hit it from a particular direction at the same angle.

4 0

2 years ago

One of the disadvantages of experimental research is that __________.

erik [133]

C I believe that would be it

8 0

2 years ago

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