Answer:

Explanation:
Given data
Mass m=67.0 kg
Final Speed vf=8.00 m/s
Initial Speed vi=2.00 m/s
Distance d=25.0 m
Force F=30.0 N
From work-energy theorem we know that the work done equals the change in kinetic energy
W=ΔK=Kf-Ki=1/2mvf²-1/2mvi²
And

So

and we know that the force the sprinter exerted Fsprinter the force of the headwind Fwind=30.0N
So
Answer:
D.None of these
Explanation:
The derivation of acceleration formula:
Let us call the 5kg mass
and the 4kg mass
. If the tension in the string is
then for the mass 
(1).
<em>(the negative sign on the right side indicates that acceleration is downwards)</em>
And for the mass 
(2).
<em> (the acceleration is upwards, hence the positive sign)</em>
Solving for
in the 2nd equation we get:
,
and putting this into the 1st equation we get:


Back to the question:
Using the formula for the acceleration we find


which is the acceleration that none of the given choices offer. Also, the acceleration of the two blocks is the same, because if it weren't, the difference in the instantaneous velocities of the objects would cause the string to break. Therefore, these two reasons make us decide that none of the choices are correct.
Answer:
See attached file :)
Hope this helps!
All the love, Ya boi Fraser :)
Answer:
The SI was and is intended to extend and refine the definitions used by the MKS.
The index of refraction of the unknown material in which a ray of light is incident at 35° and refracted at 23° is 2.03
<h3>Snell's law</h3>
index of refraction (n) = Sine i / Sine r
n = Sine i / Sine r
Where
- i is the angle of incidence
- r is the angle of refraction
<h3>How to determine the refractive index </h3>
From the question given above, the following data were obtained:
- Index of refraction of oil (nₒ) = 1.38
- Angle of incidence (i) = 35°
- Angle of refraction (r) = 23°
- Index of refraction of unknown material (nᵣ) =?
nₒSine i = nᵣSine r
1.38 × Sine 35 = nᵣ × Sine 23
Divide both side by Sine 23
nᵣ = (1.38 × Sine 35) / Sine 23
nᵣ = 2.03
Thus, the index of refraction of the unknown material is 2.03
Learn more about Snell's law:
brainly.com/question/25758484