Answer:
All the observers are correct.
Explanation:
This is simply a problem of reference frames from which the motion of the book is being viewed by the various observers.
From their various reference frames, they are all correct.
Observer A must be in the inertial reference frame.
<em>Observers who can explain the behavior of the book and the car by using the relationship between the sum of the forces and changing velocity are said to be observers in inertial reference frames.</em>
This is clearly shown by what observer A noticed. There was a relative motion between the book and the car as she pointed out, making her to be in an inertial reference frame.
<em>Similarly, observers in inertial reference frames can also explain the changes in velocity of objects by considering the forces exerted on them by other objects.</em>
This is shown by observer B as he is able to notice how the force of the car affects the velocity of the book.
Observer C is actually in a non-inertial reference frame, as newtons law of force motion relationship are no longer observed. This occurs in the non inertial reference frame.
Answer:
31.55 m/s
Explanation:
Let the initial velocity of the arrow is u metre per second.
Angle of projection, θ = 40 degree
range = 100 m
Use the formula for the range.

100 = u^2 Sin(2 x 40) / 9.8
100 x 9.8 = u^2 Sin 80
u^2 = 995.11
u = 31.55 m/s
Newton's second law tells you:
Sum of forces on an object = ma
Here, the forces acting on the bundle are the tension in the string and the force of gravity, these two must combine to yield the acceleration of the bundle.
So we have:
T-mg = ma
or T=m(g+a)
We know m=8.7kg, we need to find a from the information
starting from rest, an accelerating object covers distance according to:
<span>dist = 1/2 at^2 </span>
to cover 1m in 1.8s, we have:
a=2d/t^2 = 2x1/1.8^2 = 0.62 m/s/s
Thus, the tension in the string is:
<span>T = m(g+a)
= 8.7</span>kg(9.8m/s/s+0.62m/s/s)
<span>
<span>T = 90.654 N
</span>
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
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Yes, light enters your eye and makes things visible. It's only a small portion of the elctromagnetic spectrum. It's called "visible light." What other things does the question want to know? I could go in a describe what light really is but I think itd be unnecessary.
Note the atom of the Oxygen is electrically neutral, meaning it has equal numbers of electrons and protons.
So if it gains 2 electrons, it would have excess of 2 electrons, hence its charge would be -2.
Option B.