Consider the following situations:
a car is moving along a straight road at a constant speed.
a car is moving along a straight road while slowing down.
a car is moving along a straight road while speeding up.
a hockey puck slides along a horizontal icy (frictionless) surface.
a hockey puck slides along a rough concrete surface.
a cockroach is speeding up from rest.
a rock is thrown horizontally; air resistance is negligible.
a rock is thrown horizontally; air resistance is substantial.
a rock is dropped vertically; air resistance is negligible.
a rock is dropped vertically; air resistance is substantial.
part h
which of these situations describe the motion shown in the motion diagram at point a?
type the letters corresponding to all the right answers in alphabetical order. do not use commas. for instance, if you think that only situations c and d are correct, type cd.

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Explanation:

A motion diagram is used to represent the motion of an object. Each point represents the location of the object after equal intervals of time, and the velocity of the object is represented using arrows.

The motion diagram for this problem has been attached here. The question is asking us to analyze the motion at point A. We can make the following observations for the motion diagram at point A:

- The direction of the arrows does not change --> this means that the object is moving on a straight line

- The length of the arrows remains constant at A --> this means that the object is moving at constant speed

Of all the situations listed in the question, only two of them are compatible with these observations:

A) A car is moving along a straight road at a constant speed.

D) A hockey puck slides along a horizontal icy (frictionless) surface. (Frictionless surface means there is no friction acting on the puck, so the acceleration is zero and therefore the speed is constant).

All the other options involves a non-zero acceleration, so that the velocity is not constant. Therefore, only A and D are the correct options.

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

their crystal patterns have been disrupted by stress