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3 years ago

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A jet airplane lands with a speed of 120 mph. It has 1800 ft of runway after touch- down to reduce its speed to 30 mph. Compute

the average acceleration required of the airplane during braking A: a -8.1 ft/s2

1 answer:

bixtya [17]3 years ago

4 0

Answer:

The average acceleration is 8.06 m/s².

Explanation:

It is given that,

Initial speed of the jet, u = 120 mph = 176 ft/s

Final velocity of the jet, v = 30 mph = 44 ft/s

Distance, d = 1800 ft

We need to find the average acceleration required of the airplane during braking. It can be calculated using third law of motion as :

$v^2-u^2=2ad$

a = acceleration

$a=\dfrac{v^2-u^2}{2d}$

$a=\dfrac{(44\ ft/s)^2-(176\ ft/s)^2}{2\times 1800\ ft}$

$a=-8.06\ ft/s^2$

So, the average acceleration required of the airplane during braking is -8.06 ft/s². Hence, this is the required solution.

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A student makes a simple pendulum by attaching a mass to the free end of a 1.50-meter length of string suspended from the ceilin

Fofino [41]

Answer:

The mass has likely lost some of its mechanical energy to resistance on its path.

Explanation:

The mechanical energy of an object is the sum of its kinetic and potential energies (KE and PE.) Ideally, the mechanical energy of a simply pendulum should be "conserved." In other words, the sum of the kinetic and potential energy of the simply pendulum should stays the same as it travels along its path.

Indeed, as the pendulum travels, some of its PE will convert to KE and back. However, the sum of these two energies is supposed to stay the same.

When the pendulum moves from the highest point to the bottom of the path, some of its PE converts to KE. (The pendulum speeds up in this process.)
When the pendulum moves from the bottom of its path to the opposite side, its KE is converted back to PE. (The pendulum slows down as it moves towards the other side of the path.)

However, in practice, the mechanical energy of pendulums isn't always conserved. For example, various kinds of resistances (such as air resistance) act on the pendulum as it moves. That would slow down the pendulum. Some of the pendulum's energies would be converted to heat and is lost to the surroundings.

In effect, the mechanical energy of the pendulum would become smaller and smaller over time. When the pendulum travels back towards the girl, its potential energy would be smaller than the initial value when at the girl's chin.

5 0

3 years ago

A particle moving along the x-axis has a position given by x = (24t – 2.0t 3 ) m, where t is measured in s. What is the magnitud

Vitek1552 [10]

<h2>The magnitude 24 ( $\dfrac{m}{s^2}$ ) of the acceleration of the particle when the particle is not moving.</h2>

Explanation:

Given,

A particle moving along the x-axis has a position given by

$x=(24t-2.0t^3)$ m ........ (1)

To find, the magnitude ( $\dfrac{m}{s^2}$ ) of the acceleration of the particle when the particle is not moving = ?

Differentiating equation (1) w.r.t, 't', we get

$\dfrac{dx}{dt} =\dfrac{d((24t-2.0t^3))}{dt}$

⇒ $\dfrac{dx}{dt} =24(1)-3(2.0)t^{2} =24-6t^{2}$ ....... (2)

⇒ $24-6t^{2} = 0$

⇒ $t^{2}=2^{2}$

⇒ t = 2 s

Again, differentiating equation (2) w.r.t, 't', we get

$\dfrac{d^2x}{dt^2} =-12t$

Put t = 2, we get

$\dfrac{d^2x}{dt^2} =-12(2)=24$

Thus, the magnitude 24 ( $\dfrac{m}{s^2}$ ) of the acceleration of the particle when the particle is not moving.

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3 years ago

Why do our eyes see the color red when we look at a tomato?

forsale [732]

Answer:

B. Tomatos reflect red light

Explanation:

The only reason colors exist is because the objects with color reflect all other light except for what they are portrayed as. White reflects all colors, and black absorbs all colors.

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4 0

3 years ago

Read 2 more answers

A plane wall of thickness 0.1 mm and thermal conductivity 25 W/m K having uniform volumetric heat generation of 0.3 MW/m3 is ins

juin [17]

Answer:

The maximum temperature is 90.06° C

Explanation:

Given that

t= 0.1 mm

Heat generation

$q_g=0.3\ MW/m^3$

Heat transfer coefficient

$h=500\ W/m^2K$

Here one side(left side) of the wall is insulated so the all heat will goes in to right side .

The maximum temperature will at the left side.

Lets take maximum temperature is T

Total heat flux ,q

$q=q_g\times t$

$q=0.3\times 1000000\times 0.1 \times 10^{-3}\ W/m^2$

$q=30\ W/m^2$

So the total thermal resistance per unit area

$R=\dfrac{t}{K}+\dfrac{1}{h}$

$R=\dfrac{0.1\times 10^{-3}}{25}+\dfrac{1}{500}$

R=0.002 K/W

We know that

q=ΔT/R

30=(T-90)/0.002

T=90.06° C

The maximum temperature is 90.06° C

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3 years ago

At a certain place, Earth's magnetic field has magnitude B =0.703 gauss and is inclined downward at an angle of 75.4° to the hor

Irina18 [472]

Answer:

The charge flows in coulombs is

$dq=1.843x10^{-5}C$

Explanation:

The current magnitude of current is given by the resistance and the induced Emf as:

$I=N*\frac{dF}{Rdt}$

$\frac{dq}{dt}=\frac{dF}{Rdt}=dq=N*\frac{dF}{R}$

$dq=\frac{N*\beta*A*(Cos(\alpha_f)-Cos(\alpha_i}{R}$

$N=1300$ , $\beta=0.703$ , $A=\pi*r^2=\pi*0.10^2=0.01\pi m^2$ , $R=99.4+202=301.4$ Ω

$\alpha_f=14.6$ , $\alpha_i=165.4$

Replacing :

$dq=\frac{1300*0.703x10^{-4}*0.01\pi*(0.9667-(-0.9667))}{202+99.4}$

$dq=1.843x10^{-5}C$

5 0

3 years ago