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Nastasia [14]
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.)
Physics
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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Find the ratio of the new/old periods of a pendulum if the pendulum were transported from earth to the moon, where the accelerat
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The period of a pendulum is given by
T=2 \pi  \sqrt{ \frac{L}{g} }
where L is the pendulum length and g is the gravitational acceleration.

We can write down the ratio between the period of the pendulum on the Moon and on Earth by using this formula, and we find:
\frac{T_m}{T_e} =  \frac{2 \pi  \sqrt{ \frac{L}{g_m} } }{2 \pi  \sqrt{ \frac{L}{g_e} } }=    \sqrt{ \frac{g_e}{g_m} }
where the labels m and e refer to "Moon" and "Earth".

Since the gravitational acceleration on Earth is g_e = 9.81 m/s^2 while on the Moon is g_m=1.63 m/s^2, the ratio between the period on the Moon and on Earth is
\frac{T_m}{T_e}= \sqrt{ \frac{g_e}{g_m} }= \sqrt{ \frac{9.81 m/s^2}{1.63 m/s^2} }=2.45

3 0
2 years ago
Consider a system to be two train cars traveling toward each other. What is the total momentum of the system before the train ca
Brut [27]

Let say the two train cars are of masses m_1 and m_2

now if the speed of two cars are v_1 and v_2

then we can say that the momentum of two cars before they collide is given by

P = m_1v_1 - m_2v_2

here two cars are moving in opposite direction so we can say that the net momentum is subtraction of two cars momentum.

Now since in these two car motion there is no external force on them while they collide

So the momentum of two cars are always conserved.

hence we can say that the final momentum of two cars will be same after collision as it is before collision

P = m_1v_1 - m_2v_2

5 0
3 years ago
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__________ are scientists that study the composition of earth including rock layers at the surface.
insens350 [35]

Answer:

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Explanation:

please mark me brainliest

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2 years ago
In calisthenics, the resistance is ultimately provided by __________. A. free weights B. springs and elastic bands C. gravity D.
tangare [24]

Answer:

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Explanation:

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2 years ago
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A hot air balloon rising vertically is tracked by an observer located 3 miles from the lift-off point. At a certain moment, the
yuradex [85]

Answer:

\frac{dy}{dt}=1.2\frac{mi}{min}

Explanation:

We know that the tangent function relates the angle of the right triangle that forms the hot air balloon rising:

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Differentiating (1) with respect to time, we get:

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\frac{dx}{dt}=0 since x is a constant value. Replacing:

\frac{dy}{dt}=3mi(sec^{2}\frac{\pi}{3})0.1\frac{rad}{min}\\\frac{dy}{dt}=1.2\frac{mi}{min}

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3 years ago
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