ayka0219
contestada

Motion equation of object is
[tex]x = 15 - 12t + 3 {t}^{2} [/tex]
How long did it move until it stops?
(I think it is projectile motion, I'm not sure.)

A) 5 sec
B) 0,3 sec
C) 0,4 sec
D) 4 sec
E) 2 sec

Respuesta :

LammettHash

Take the derivative to find the velocity of the object:

[tex]v=\dfrac{\mathrm dx}{\mathrm dt}=-12+6t[/tex]

The object stops when [tex]v=0[/tex]:

[tex]-12+6t=0\implies6t=12\implies t=2[/tex]

so the answer is E.

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