<h2>
Kinetic energy just before hitting the floor is 324.57 J</h2>
Explanation:
Weight of volleyball player = 650 N
That is
Mass x Acceleration due to gravity = 650
Mass x 9.81 = 650
Mass = 66.26 kg
We also have equation of motion v² = u² + 2as
Initial velocity, u = 0 m/s
Acceleration, a = 9.81 m/s²
Final velocity, v = ?
Displacement, s = 0.5 m
Substituting
v² = u² + 2as
v² = 0² + 2 x 9.81 x 0.5
v = 3.13 m/s
Velocity with which he lands on ground is 3.13 m/s
We have kinetic energy = 0.5 x Mass x Velocity²
Substituting
Kinetic energy = 0.5 x 66.26 x 3.13²
Kinetic energy = 324.57 J
Kinetic energy just before hitting the floor is 324.57 J
Principle: Pythagorean theorem
Given:
Let a = boat velocity = 25 miles per hour
b = river velocity = 10 miles per hour
Required: c = actual velocity
Solution:
c^2 = a^2 + b^2
c^2 = (25)^2 + (10)^2
c^2 = 725
(c^2)^0.5 = (725)^0.5
c = 26.93 miles per hour
<em>ANSWER: Actual boat velocity is 26.93 miles per hour</em>
Answer: UVA rays occupy the frequency range between 7.1 . 10¹⁴ and 9.4. 10¹⁴ Hz.
Explanation:
UV rays are simply electromagnetic waves, which wavelength is just below the visible spectrum (hance the name ultraviolet, meaning beyond violet).
As any elecromagnetic wave, propagates in the free space at the same speed that light does, i.e. 3.10⁸ m/s.
Also, we know that there exists a direct relationship between the wave speed, her wavelength (distance travelled by the wave during one cycle time) and the frequency (the inverse of the time needed to complete one cycle).
This relationship can be written as the following equation:
v = λ . f ⇒ f = v/λ
Replacing by the extreme wavelengths, we find the corrresponding limit frequencies as follows:
f₁ = 3.10⁸ m/s / 320 . 10⁻⁹ m ⇒ f₁ = 9.4 . 10¹⁴ Hz.
f₂ = 3.10⁸ m/s / 400 . 10⁻⁹ m ⇒ f₂ = 7.1 . 10¹⁴ Hz.
