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3 years ago

8

If the kinetic energy of an electron is 4.1e-18 j, what is the speed of the electron? (you can use the approximate (nonrelativis

tic) formula here.)

1 answer:

arlik [135]3 years ago

3 0

The kinetic energy of the electron is
$K= \frac{1}{2}mv^2$
where $m=9.1 \cdot 10^{-31} kg$ is the mass of the electron and v its speed. Since we know the value of the kinetic energy, $K=4.1 \cdot 10^{-18} J$ , we can find the value of the speed v:
$v= \sqrt{ \frac{2K}{m} }= \sqrt{ \frac{2\cdot 4.1 \cdot 10^{-18}J}{9.1 \cdot 10^{-31}kg} } = 3\cdot 10^6 m/s$

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A 68-kg skydiver has a speed of 52 m/s at an altitude of 670 m above the

Arlecino [84]

Answer:

91936J

Explanation:

We know that kinetic energy= 1/2 mv^2

M= mass = 68 Kg

v= velocity= 52 m/s

KE=1/2 × 68 × (52)^2

KE= 1/2 × 68 × 2704

KE= 91936J

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3 years ago

What physics is involved for a passenger feeling pushed backward into the seat of an airplane when it accelerates along the runw

timofeeve [1]

It's due to Inertia. The law of Inertia states that a body will try to retain its movement state if possible. This means, if a body is at rest, it will try to remain at rest using forces. Similarly, if it's in movement, it will try to remain in movement.

In this example, the plane is moving forwards, and so do the seats, which in turn push the passenger forwards.The force felt is Inertia acting on the body, trying to counter the movement.

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3 years ago

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A pesky rabbit has been feeding on Mrs. Cromwell’s prized flowers. In order to put an end to this she devised the simple trap be

Ivahew [28]

Answer:

The minimum diameter of the stick to bear the normal stress as 100 psi is 0.1785 in.

Explanation:

Taking moment along point A

$\sum M_A=0\\F_{BC} sin 60 \times 48 -13 \times 8=0\\F_{BC}=2.502 lb_f$

Also normal stress is given as 100 psi

Now

$\sigma=\frac{F}{A}\\100=\frac{2.502}{\pi \frac{d^2}{4}}\\d^2 =\frac{4 \times 2.502}{100 \pi }\\d^2=0.031856\\d=\sqrt{0.031856}\\d=0.1785 inch$

The minimum diameter of the stick to bear the normal stress as 100 psi is 0.1785 in.

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3 years ago

Use the graph above to determine the change in speed of the object between 20 and 30 seconds?

allsm [11]

Answer:

6 m/s

Explanation:

To determine the change in speed of the object, we just need to determine its speed at t = 30 s and at t = 20 s, and then calculate the difference.

The speed at t = 30 is:

v = 6 m/s

While the speed at t = 20 s is:

u = 0

Therefore, the change in speed is:

$\Delta v = v-u=6-0 = 6 m/s$

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3 years ago

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To practice Problem-Solving Strategy 27.1: Magnetic Forces. A particle with mass 1.81×10−3 kgkg and a charge of 1.22×10−8 CC has

Roman55 [17]

Answer:

The magnitude of the acceleration is $a = 0.33 m/s^2$

The direction is $- \r k$ i.e the negative direction of the z-axis

Explanation:

From the question we are that

The mass of the particle $m = 1.8*10^{-3} kg$

The charge on the particle is $q = 1.22*10^{-8}C$

The velocity is $\= v = (3.0*10^4 m/s ) j$

The the magnetic field is $\= B = (1.63T)\r i + (0.980T) \r j$

The charge experienced a force which is mathematically represented as

$F = q (\= v * \= B)$

Substituting value

$F = 1.22*10^{-8} (( 3*10^4 ) \r j \ \ X \ \ ( 1.63 \r i + 0.980 \r j )T)$

$= 1.22 *10^{-8} ((3*10^4 * 1.63)(\r j \ \ X \ \ \r i) + (3*10^4 * 0.980) (\r j \ \ X \ \ \r j))$

$= (-5.966*10^4 N) \r k$

Note :

$i \ \ X \ \ j = k \\\\j \ \ X \ \ k = i\\\\k \ \ X \ \ i = j\\\\j \ \ X \ \ i = -k \\\\k \ \ X \ \ j = -i\\\\i \ \ X \ \ k = - j\\$

Now force is also mathematically represented as

$F = ma$

Making a the subject

$a = \frac{F}{m}$

Substituting values

$a =\frac{(-5.966*10^4) \r k}{1.81*10^{-3}}$

$= (-0.33m/s^2)\r k$

$= 0.33m/s^2 * (- \r k)$

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3 years ago