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:
Explanation:
The football players collide in a completely inelastic collision, in other words they have the same velocity after the collision, this velocity has a magnitude V=1.6m/s.
We need to use the conservation of momentum Law, the total momentum is the same before and after the collision, at the initial point the receiver does not have any speed
(1)
We solve in order to find the receiver mass:
Answer:
I think D it could maybe B
Answer:

Explanation:
Since the system is in international space station
so here we can say that net force on the system is zero here
so Force by the astronaut on the space station = Force due to space station on boy
so here we know that
mass of boy = 70 kg
acceleration of boy = 
now we know that


now for the space station will be same as above force




Hey there!:
Here the Statement - D is correct.
Because Orbitals containing the core electrons are more attracted towards nuclear charge and hence less shilded from nuclear charge than an orbital that doesn't penetrate. Also due to more attraction between the orbital containing core electron and nucleus, it will have less energy.
Hope this helps!