The correct option is D.
The model developed by Ptolemy has a lot of inconsistency and during the middle age additional explanation was offered for the claims made by the model. The model was very complicated because it was based on erroneous assumptions.
Copernicus model was simpler and some of his claims were correct.<span />
Options A and D are correct. The strength of the force of friction depends on the objects' sizes and weights and the heat generated by the friction and the types of surfaces involved.
<h3 /><h3>What is the friction force?</h3>
It is a type of opposition force acting on the surface of the body that tries to oppose the motion of the body. its unit is Newton (N).
Mathematically, it is defined as the product of the coefficient of friction and normal reaction.
On resolving the given force and acceleration in the different components and balancing the equation gets. Components in the x-direction.
The strength of the force of friction depends on the two factors, as;
A. The objects' sizes and weights.
D. The heat generated by the friction and the types of surfaces involved.
Hence, options A and D are correct.
To learn more about the friction force, refer to the link;
brainly.com/question/1714663
#SPJ1
Here is the rule for see-saws here on Earth, and there is no reason
to expect that it doesn't work exactly the same anywhere else:
(weight) x (distance from the pivot) <u>on one side</u>
is equal to
(weight) x (distance from the pivot) <u>on the other side</u>.
That's why, when Dad and Tiny Tommy get on the see-saw, Dad sits
closer to the pivot and Tiny Tommy sits farther away from it.
(Dad's weight) x (short length) = (Tiny Tommy's weight) x (longer length).
So now we come to the strange beings on the alien planet.
There are three choices right away that both work:
<u>#1).</u>
(400 N) in the middle-seat, facing (200 N) in the end-seat.
(400) x (1) = (200) x (2)
<u>#2).</u>
(200 N) in the middle-seat, facing (100 N) in the end-seat.
(200) x (1) = (100) x (2)
<u>#3).</u>
On one side: (300 N) in the end-seat (300) x (2) = <u>600</u>
On the other side:
(400 N) in the middle-seat (400) x (1) = 400
and (100 N) in the end-seat (100) x (2) = 200
Total . . . . . . . . . . . . <u>600</u>
These are the only ones to be identified at Harvard . . . . . . .
There may be many others but they haven't been discarvard.
The best position for the person would be outside, under a clear sky, standing up. He should do it sometime between sunset and sunrise, from a day before until a day after the moment of Full Moon.
