Answer:
due to the inertia of motion, the fan continues to move for some time even after switching it off.
Acceleration = (change in speed) / (time for the change)
-- You said that the airplane has to speed up from zero ("sitting") to 40 m/s, so the change in speed is 40 m/s.
-- You said that it has to roll for 10 seconds to build up enough speed to take off, so the time for the change is 10 s .
Acceleration = (40 m/s) / (10 s)
Acceleration = (40/10) (m/s)/s
<em>Acceleration = 4 m/s²</em>
That seems like no problem. It's only like about 41% of 1 G . That would not even spill the drinks in First Class, or wake up the passengers who are already asleep (like me).
Answer: d₂ = 170 mGya
Explanation:
the relationship between absonbed 'd' and exposure 'E' is given as;
D(Gv) = F . x (AS/xB)
F is a conversion coefficient depending on medium
so we can simply write
d₁/d₂ = x₁/x₂
Given that;
our x₁ = 60 mAs, x₂ = 120 mAs, d₁ = 85 mGya, d₂ = ?
from the given formula,
d₂ = (x₂d₁ / x₁)
now we substitute
d₂ = (120 × 85) / 60
d₂ = 170 mGya
∴ if 120 mAa is used, the new exposure will be 170 mGya
Answer:
The wavelength is 173 nm.
Explanation:
This kind of phenomenon is known as photoelectric effect, it occurs when photons of light inside the metal surface and if they have the right amount of energy electrons absorb it and got expelled from the metal as photo electrons. The maximum kinetic energy of that photo electrons is given by the expression:
(1)
With E the energy of the photon and Φ the work function of the material. The work function is a value characteristic of each material and is related with how much the electron is attached to the material, the energy of the photon is the Planck's constant (h=
) times the frequency of light (
) , then (1) is:
(2)
The frequency of an electromagnetic wave is related with the wavelength (
) by:
(3)
with c the velocity of light (c=
)
Using (3) on (2):
Solving for 
:
That's the work function of the metal we're dealing. So now if we want to know the wavelength to obtain the double of the kinetic energy we use:
Solving for :
Answer:
V₂ = - m₁ V₁ / m₂
Explanation:
According to law of conservation of momentum, "Total momentum of an isolated system remains constant. i.e
Pi = Pf
We consider ball and catapult an isolated system.
before launching ball momentum of the system is zero.
After launching ball momentum of ball is:
Pb= 0.1 * 500 = 50 kg m/s
Now according to law of conservation of momentum:
Pf = Pi
⇒ Pb + Pc = 0
Let Pb= m₁ V₁
& Pc = m₂ V₂
So
m₁ V₁ + m₂ V₂ = 0
⇒ V₂ = - m₁ V₁ / m₂
The negative sing shows that catapult velocity will have opposite direction to the ball velocity.
