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1 answer:
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The final speed of the object is 15.3 m/s
Explanation:
The object in the problem is moving by uniformly accelerated motion (it is in free fall), so we can use the following suvat equation:
where
v is the final velocity
u is the initial velocity
is the acceleration of gravity (taking downward as positive direction)
s is the vertical displacement
For the object in this problem:
u = 0 (it starts from rest)
s = 12 m is the displacement of the object
Solving for v,
Learn more about free fall motion here:
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Answer:
a) the longest wavelength of the light that will eject electrons from the silicon surface is 258.7891 nm
b) maximum kinetic energy will electrons reach the anode is 0.5098 eV
Explanation:
Given:
Wavelength range = 141-295 nm
Potential of 3.5 V
For the silicon, the work function is Φ = 4.8 eV = 7.68x10⁻¹⁹J
Questions:
a) What is the longest wavelength of the light that will eject electrons from the silicon surface, λ = ?
b) With what maximum kinetic energy will electrons reach the anode,
a) The longest wavelength that will eject electrons:
Here
h = Planck's constant = 6.625x10⁻³⁴J s
c = speed of light = 3x10⁸m/s
Substituting values:
b) The maximum kinetic energy (one electron):
Now, you need to calculate the potential difference:
Here
e = charge of electron = 1.6x10⁻¹⁹C
Substituting:
Now, the maximum kinetic energy of the electrons:
Kmax = 4.0098 - 3.5 = 0.5098 eV
Answer:
1879.33J
874.1W
Explanation:
Given parameters:
Distance covered = 2.91m
Time taken = 2.15s
Mass of Bart = 65.9kg
Unknown:
Work done = ?
Power rating = ?
Solution:
Here, the work done is related to the the potential energy in climbing this flight of stairs.
Work done = Potential energy = mgH
where m is the mass
g is the acceleration due to gravity
H is the height
Work done = 65.9 x 9.8 x 2.91 = 1879.33J
Power is defined as the rate at which work is being done.
Power =
=
= 874.1W