Physics, 20.03.2020 23:57 avelyp

The thrust produced by a single jet engine creates a force of F = 86000 N. It takes the jet (with a mass of m = 7200 kg) a distance of d = 0.92 km to take off. show answer Correct Answer 50% Part (a) What is the take-off speed of the jet vt in m/s? vt = 148.25 vt = 148.3 ✔ Correct! show answer No Attempt 50% Part (b) How far in meters would you need to depress a giant spring k = 100,000 N/m in order to launch the jet at the same speed without help from the engine? ds = | sin() cos() tan() cotan() asin() acos() atan() acotan() sinh() cosh() tanh() cotanh() Degrees Radians π ( ) 7 8 9 HOME E ↑^ ^↓ 4 5 6 ← / * 1 2 3 → + - 0 . END √() BACKSPACE DEL CLEAR

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Answer from: josephrosanne18

a) The take-off speed of the jet is approximately 148.249 meters per second.

b) The spring deformation is approximately 39.779 meters.

Let suppose that the jet accelerates on a horizontal ground.

a) The final speed of the jet (), in meters per second, is determined by Work-Energy Theorem:

$\frac{1}{2}\cdot m\cdot v^{2} = F\cdot s$ (1)

Where:

- Mass of the jet, in kilograms.

- Thrust of the jet engine, in newtons.

- Take-off distance, in meters.

If we know that $m = 7200\,kg$ , $F = 86000\,N$ and $s = 920\,m$ , then the take-off speed is:

$v = \sqrt{\frac{2\cdot F\cdot s}{m} }$

$v = \sqrt{\frac{2\cdot (86000\,N)\cdot (920\,m)}{7200\,kg} }$

$v \approx 148.249\,\frac{m}{s}$

The take-off speed of the jet is approximately 148.249 meters per second.

b) By principle of energy conservation, the change in translational kinetic energy ( $\Delta K$ ), in joules, is equal to the change in elastic potential energy ( $\Delta U$ ), in joules. By applying the definition of translational kinetic energy and elastic potential energy, we get the resulting formula:

$\frac{1}{2}\cdot m \cdot v^{2} = \frac{1}{2}\cdot k\cdot x^{2}$ (2)

Where:

- Spring constant, in newtons per meter.

- Spring deformation, in meters.

Now, we clear within the expression:

$x = \sqrt{\frac{m}{k} }\cdot v$ (3)

If we know that $m = 7200\,kg$ , $k = 100000\,\frac{N}{m}$ and $v \approx 148.249\,\frac{m}{s}$ , then the spring deformation is:

$x = \sqrt{\frac{7200\,kg}{100000\,\frac{N}{m} } }\cdot \left(148.249\,\frac{m}{s} \right)$

$x \approx 39.779\,m$

The spring deformation is approximately 39.779 meters.

We kindly invite to check this question on energy conservation: link

Answer from: savannahbrookec2896

a) take off speed of jet in m/s = 148.3 m/s

b) we need to depress a spring for distance of 39.79 m.

Explanation:

Given:

F = 86000 N

m =7200 kg

d = 0.92 Km= 920 m

a) To find take off speed of jet in m/s

We know that work done is given by

W = F x d ...........(equation 1)

F is force and d is displacement

Also work done in terms of kinetic energy KE and potential energy PE is given by

W = PE + KE

PE = $\frac{1}{2}$ m $v^{2}$

Initial velocity is zero hence, PE = 0

Hence W = KE

W = $\frac{1}{2}$ m $vt^{2}$ ................(equation 2)

From equation 1 and 2, we get

F x d = $\frac{1}{2}$ m $vt^{2}$

vt = $\sqrt{\frac{2Fd}{m} }$

= $\sqrt{\frac{2 x 86000 x 920}{7200} }$

=148.25

vt = 148.3 m/s

Hence proved

b) To find how far giant spring must be depressed (in meters)

Given

spring constant K = 100000 N/m

We know that for a spring, kinetic energy KE is equal to elastic potential energy EPE

KE = $\frac{1}{2}$ m $vt^{2}$

EPE = $\frac{1}{2}$ k $x^{2}$ , where k is spring constant and x is displacement (here distance of depression)

KE = EPE

$\frac{1}{2}$ m $vt^{2}$ = $\frac{1}{2}$ k $x^{2}$

x = $\sqrt{\frac{mv^{2} }{k} }$

= $\sqrt{\frac{7200 x 148.3^{2} }{100000} }\\$

= 39.79 m

Hence we need to depress a spring of 39.79 m.

Answer from: Quest

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm. the wire diameter is d = 0.9 mm. the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2) in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

Answer from: Quest

Sorry i don’t know what to do

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The thrust produced by a single jet engine creates a force of F = 86000 N. It takes the jet (with a...