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:
147 J
Explanation:
The energy transferred to potential energy is :
U = m * g * h = (5 kg) * (9.8 m/s^2) * (3 m) = 147 J
Answer:
Explanation:
There are different theories and evidence about the big bang, in this case, we're going to see three evidence.
The galaxies are moving from us, this means space is expanded, this in consequence Big Bang's explosion.
The cosmic microwave background radiation is related to the early warmth of the universe.
The observed abundance of hydrogen, helium, deuterium, lithium, these are checked from the spectra of the oldest stars.
