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22. Kerry Klutz drops her physics book off her aunt’s high rise balcony. It hits the ground below 1.5 s later.
a. With what speed does it hit?
b. How high is the balcony (ignore air drag).

Respuesta :

AL2006
a). Gravity makes falling objects fall 9.8 m/s faster every second.
After 1.5 seconds, it's falling at (1.5 x 9.8) = 14.7 m/s .

b). The average speed of the physics book is (1/2) (0 + 14.7) = 7.35 m/s .

Falling at an average speed of 7.35 m/s for 1.5 seconds,
the book falls

(1.5 x 7.35) = 11.025 meters 

Answer:

Part (a) v = 14.7 m/s

Part (b) h = 11.025 m

Explanation:

Part (i)

As we know that book is moving under constant acceleration which is due to gravity

so here we know that

[tex]a = 9.8 m/s^2[/tex]

[tex]\Delta t = 1.5 s[/tex]

[tex]v_i = 0[/tex]

so here we will have

[tex]v_f = v_i + at[/tex]

[tex]v_f = 0 + (9.8)(1.5)[/tex]

[tex]v_f = 14.7 m/s[/tex]

Part (b)

height of balcony can be found by another kinematics equation

[tex]\Delta y = v_i t + \frac{1}{2}at^2[/tex]

[tex]\Delta y = 0 + \{1}{2}(9.8)(1.5)^2[/tex]

[tex]\Delta y = 11.025 m[/tex]

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