The voltage between the cathode and the screen of a television set is 22 kV. If we assume a speed of zero for an electron as it
1 answer:
Answer:
v= 8.8*10⁷ m/s
Explanation:
- Assuming no friction present, the change in electrical potential energy, must be equal in magnitude, to the change in kinetic energy of the electron.
- The change in the electrical potential energy, can be expressed as follows:
- The change in kinetic energy, assuming that the electron started from rest, can be written as follows:
⇒
- From the equation above, replacing by ΔK and ΔU, we have:
- Solving for v:
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(a) 29.8 m/s
To solve this problem, we start by analyze the vertical motion first. This is a free fall motion, so we can use the following suvat equation:
where, taking upward as positive direction:
is the final vertical velocity
is the initial vertical velocity (zero because the pebble is launched horizontally)
is the acceleration of gravity
s = -25.0 m is the displacement
Solving for vy,
(downward, so we take the negative solution)
The pebble also have a horizontal component of the velocity, which remains constant during the whole motion, so it is
So, the final speed of the pebble as it strikes the ground is
(b) 29.8 m/s
In this case, the pebble is launched straight up, so its initial vertical velocity is
So we can find the final vertical velocity using the same suvat equation as before:
(downward, so we take the negative solution)
The horizontal speed instead is zero, since the pebble is initially launched vertically, so the final speed is just equal to the magnitude of the vertical velocity:
v = 29.8 m/s
(c) 29.8 m/s
This case is similarly to the previous one: the only difference here is that the pebble is launched straight down instead than up, therefore
Using again the same suvat equation:
(downward, so we take the negative solution)
As before, the horizontal speed instead is zero, since the pebble is initially launched vertically, so the final speed is just equal to the magnitude of the vertical velocity:
v = 29.8 m/s
We notice that the final value of the speed is always the same in all the three parts, so it does not depend on the direction of launching. This is due to the law of conservation of energy: in fact, the initial mechanical energy of the pebble (kinetic+potential) is the same in all three cases (because the height h does not change, and the speed v does not change either), and the kinetic energy gained during the fall is also the same (since the pebble falls the same distance in all 3 cases), therefore the final speed must also be the same.
Answer:
<h3>The answer is 8.5 kg</h3>Explanation:
The mass of the object can be found by using the formula
where
f is the force
a is the acceleration
So we have
We have the final answer as
<h3>8.5 kg</h3>Hope this helps you