Solution
x(t) = 8 cos t, x(5π/6)= 8 cos(<span>5π/6)
</span>cos(5π/6)=cos(3π/6 + 2π/6 )=cos(π/3 +π/2)= - sin π/3 (cos (x+<span>π/2)= -sinx)
</span>x(t) = -8sin <span>π/3 = - 4 .sqrt3
</span>v(t) = -8sint = -8sin (π/3 +<span>π/2)= -8 cosπ/3 </span>(sin (x+π/2)= cosx)
v(t) =<span> -8 cosπ/3 = -8/2= - 4
</span>a(5π/6) = - 8cost = -(- sin π/3)= 4 .<span>sqrt3
</span>a(5π/6) = 4 .<span>sqrt3</span>
The answer is b after I finish my test ill give you the anwsers
<em>The correct answer is option</em><em> B.</em> The maximum height that can be reached by the stone is determined as 11.5 m.
<h3>
Maximum height attained by the stone </h3>
The maximum height attained by the stone when it is a 2/3 of its total height is calculated as follows;
v² = u² - 2gh
where;
- v is final velocity at maximum height, v = 0
- u is initial velocity
- g is acceleration due to gravity
0 = u² - 2gh
2gh = u²
h = u²/2g
h = (15²)/(2 x 9.8)
h = 11.48 m
h = 11.5 m
Thus, the maximum height that can be reached by the stone is determined as 11.5 m
Learn more about maximum height here: brainly.com/question/12446886
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