Right / Wrong?

Question

A stone is fired with a slingshot from the top of a cliff straight downward,which is the negative direction.The initial speed is 9m/s^2. A.) What is the aceleration(Magnitude and direction) of the stone during the downward motion? Is the stone decelerating B.) after 0,5s how far Below the cliff is the stone.------A.)-9,8m/s^2 due south ,no B.) 5,725m

INITIAL SPEED IS 9 M/S not 9M/s^2
Correction

Answer 1

To really answer this question you would need to know what the stone looks like. There would be air resistance and a terminal velocity determined by the stone's shape. Thus the stone might (and in an air environment likely would) slow down after its initial release.

However, given the problem at hand (by assuming that this is a high-school or entry-level college physics class) I will continue under the assumption that we are neglecting air resistance effects..

so the initial velocity is 9m/s.

answers:

a) the acceleration of the object is 9.8m/s^2 downward. If you neglect air resistance, the initial velocity of the object doesn't matter; it will continue to accelerate at 9.8 m/s^2. Again neglecting air resistance, the stone is not decelerating but will continuously accelerate. If air resistance is taken into effect the problem doesn't contain sufficient information to answer.

b) position. The formula for an object with an initial velocity undergoing a constant acceleration is. x = v0 * t + 1/2 * a * t^2

Since t=.5, v0=9, and a=9.8, this formula becomes x=9*.5+1/2(9.8)(.5)^2 = 4.9+1/2(9.8)(.25) = 4.5+ 1.225 = 5.725 The rock would therefore be located 5.725 below the point from which it was thrown downward after one second.

In other words, you are spot on with your answers. Good job; you are absoloutely correct!.

Answer 2

after the stone is fired the acceleration is "g"=9.806m/s^2 and direction is downward,

No, velocity of the stone will increase with time because initial velocity and the acceleration both have the same direction;

after 0.5s it will travel 5.725

Answer 3

Your answer to A is incorrect because you have specified two directions. If the stone is moving straight down, it cannot be moving South. Your answer to B is correct.