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3 years ago

Human muscles have an efficiency of about

Physics

1 answer:

ryzh [129]3 years ago

8 0

Answer: the answer is B. 18 to 26%

Explanation: I took the practice test on Edge and I got it right :)

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Suppose electrons in a TV tube are accelerated through a potential difference of 2.00 104 V from the heated cathode (negative el

Ivanshal [37]

Answer:

83816746.4254 m/s

Explanation:

m = Mass of electron = $9.11\times 10^{-31}\ kg$

q = Charge of electron = $1.6\times 10^{-19}\ C$

V = Voltage = $2\times 10^4\ V$

The kinetic energy of the electron is

$K=\dfrac{1}{2}mv^2$

Energy is given by

$E=qV$

Balancing the energy

$qV=\dfrac{1}{2}mv^2\\\Rightarrow v=\sqrt{\dfrac{2qV}{m}}\\\Rightarrow v=\sqrt{\dfrac{2\times 1.6\times 10^{-19}\times 2\times 10^4}{9.11\times 10^{-31}}}\\\Rightarrow v=83816746.4254\ m/s$

The velocity of the electrons is 83816746.4254 m/s

5 0

3 years ago

At take off, a plane flies 100 km north before turning to fly 200 km east. How far is its destination from where the plane took

Snowcat [4.5K]

The answer is 300 km

To the destination

4 0

3 years ago

A giant wall clock with diameter d rests vertically on the floor. The minute hand sticks out from the face of the clock, and its

Katyanochek1 [597]

Answer:

$d_{x}(t)=(D/2)cos(\frac{\pi}{30}*t)$

Explanation:

We can try writing the equation of the horizontal component of the length of the minute hand in terms of distance and the angle, that depends of time in this particular case.

The x-component of the length of the minute hand is:

$d_{x}(t)=dcos(\theta (t))$ (1)

d is the length of the minute hand (d=D/2)
D is the diameter of the clock
t is the time (min)

Now, using the angular kinematic equations we can express the angle in term of angular velocity and time. As we know, the minute hand moves with a constant angular velocity, so we can use this equation:

$\theta (t)=\omega *t$ (2)

Also we know, that the minute hand moves 90 degrees or π/2 rad in 15 min, so using the definition of angular velocity, we have:

$\omega=\frac{\Delta \theta}{\Delta t}=\frac{\theta_{f}-\theta_{i}}{t_{f}-t{i}}=\frac{\pi/2-0}{15-0}=\frac{\pi}{30}$

Now, let's put this value on (2)

$\theta (t)=\frac{\pi}{30}*t$

Finally the length x(t) of the shadow of the minute hand as a function of time t, will be:

$d_{x}(t)=(D/2)cos(\frac{\pi}{30}*t)$

I hope it helps you!

6 0

3 years ago

What is the period in seconds for 10 oscillations in 5 seconds

saul85 [17]

Answer:

I think the answer is half a second cause Time period = Time taken by the pendulum/Number of oscillations made by the pendulum so 5 divided by 10 equals 0.5 which is half a second

5 0

3 years ago

The field of physics which deals with the study of probability waves that describe the motion and dynamics of particles with mas

goldenfox [79]

Answer:

Option B. quantum mechanics

Explanation:

Quantum Mechanics, at atomic and sub-atomic levels deal with the study of how particles at this level behave and how the matter and energy interacts.

It also explains the properties of atoms, molecules and the particles constituting these.

The wave- particle duality of quantum mechanics that says that matter or every quantum of it exhibits wave as well as particle nature.

This theory was incorporated with its mathematical description given by Schrodinger was also incorporated in the theory for eave-particle duality and The probability for the existence of particle was determined.

4 0

3 years ago