Answer:
a) KE = 888.26J
b) N = 294.5 turns
Explanation:
For the kinetic energy:
The inertia is:
So, the kinetic energy will be:
Now, friction force is:
Ff = μ*N = 0.80*5N = 4N
The energy balance would be:
Kf - Ko = Wf where Kf=0; Ko = 888.26J; and Wf is the work done by friction force.
Wf = -Ff*d = -Ff*N*2*π*R where N is the amount of turns it gives.
Replacing these values into the energy balance:
0-888.26=-4*N*2*π*0.12
-888.26=-0.96*π*N
N=294.5 turns
Answer:
Part A
The intensity is
Part B
The intensity is
Explanation:
From the question we are told that
The intensity of the light detected by first eye is
Now at initial state according the question the light ray is perpendicular to the eye so it means that it is at 90° the eye
Now the first question is to obtain the intensity the first eye (the first in this case is the one focused on the light )would detect when the head is rotated by 20° its previous orientation
This is mathematically evaluated as
Now the second question is to obtain the intensity the first eye (the first eye in this case is the one that is not focused on the light )would detect when the head is rotated by 20° its previous orientation
Now in this case the angle between the eye and the light is 90-20 = 70°
So
Answer:
Explanation:
The average velocity is total displacement divided by time:
And in the case of vertical
where is the total vertical displacement of the rock.
The vertical displacement of the rock when it is thrown straight up from height with initial velocity
is given by:
The time it takes for the rock to reach maximum height is when , and it is
The vertical distance it would have traveled in that time is
This is the maximum height the rock reaches, and after it has reached this height the rock the starts moving downwards and eventually reaches the ground. The distance it would have traveled then would be:
Therefore, the total displacement throughout the rock's journey is
Now wee need to figure out the time of the journey.
We already know that the rock reaches the maximum height at
and it should take the rock the same amount of time to return to the roof, and it takes another to go from the roof of the building to the ground; therefore,
where is the time it takes the rock to go from the roof of the building to the ground, and it is given by
we solve for using the quadratic formula and take the positive value to get:
Therefore the total time is
Now the average velocity is