Please help me 17) A student stands at the edge of a cliff and throws a stone ho

Question

Please help me

17) A student stands at the edge of a cliff and throws a stone horizontally over the edge with a speed of

vi = 19.0 m/s.

The cliff is

h = 58.1 m

above a body of water as shown in the figure below.

(a) What are the coordinates of the initial position of the stone?

(e) Write symbolic equations for the x and y components of the velocity of the stone as a function of time. (Use the following as necessary: vix, g, and t. Indicate the direction of the velocity with the sign of your answer.)

(f) Write symbolic equations for the position of the stone as a function of time. (Use the following as necessary: vix, g, and t. Indicate the direction of the displacement with the sign of your answer.)

Yf =?

15) A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 8.10 m/s at an angle of 19.0° below the horizontal. It strikes the ground 6.00s later.

(a) How far horizontally from the base of the building does the ball strike the ground?
m

(b) Find the height from which the ball was thrown.
m

(c) How long does it take the ball to reach a point 10.0 m below the level of launching?
s

Explanation / Answer

(a)

Considering the cliff is at y-axis, As the height of the cliff is h = 58.1 m, therefore

the coordinates of the initial position of the stone are

xi = 0 m

yi = 45.0 m

(e)

vx = vix + ax*t

vix = 19 m/s , ax = 0

so,

vx = 19

vy = viy + ay*t

viy = 0 ,

And the vertical acceleration of the stone is equal to -g (the free fall accelaration). Therefore ay = -g

so,

vy = -g*t (negative sign indicates that the velocity is along negative y-direction)

(f)

Now the equations of x and y are as shown below.

x = vix*t

x = 19*t

y = yo + viy*t +1/2*ay*t2

y = 58.1 + 0 + 1/2*(-g)*t2

y = 58.1 - 1/2*g*t2  or we can write

y = 58.1 - 4.9*t2

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