Soru
An object is thrown straight up with a velocity in ft/s given by v(t)=-32t+67 where tis in seconds, from a height of 42 feet. a) What is the object's initial velocity? 67ft/s b) What is the object's maximum velocity? 67ft/s ft c) What is the object's maximum displacement? square square d) When does the maximum displacement occur? (67)/(32) e) When is the object's displacement 0? square f) What is the object's maximum height? square ft Note: You can earn partial credit on this problem.
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c) To find the object's maximum displacement, we need to find the time when the velocity is 0. We can do this by setting the velocity equation equal to 0 and solving for t:<br /><br />$-32t + 67 = 0$<br /><br />$32t = 67$<br /><br />$t = \frac{67}{32}$<br /><br />Now, we can plug this value of t back into the displacement equation to find the maximum displacement:<br /><br />$x(t) = -16t^2 + 67t + 42$<br /><br />$x(\frac{67}{32}) = -16(\frac{67}{32})^2 + 67(\frac{67}{32}) + 42$<br /><br />$x(\frac{67}{32}) = -16(\frac{4489}{1024}) + 67(\frac{67}{32}) + 42$<br /><br />$x(\frac{67}{32}) = -71.40625 + 141.09375 + 42$<br /><br />$x(\frac{67}{32}) = 111.6875$<br /><br />Therefore, the object's maximum displacement is 111.6875 feet.<br /><br />d) The maximum displacement occurs at the time when the velocity is 0, which we found to be $\frac{67}{32}$ seconds.<br /><br />e) To find when the object's displacement is 0, we need to solve the displacement equation for t:<br /><br />$x(t) = -16t^2 + 67t + 42$<br /><br />$-16t^2 + 67t + 42 = 0$<br /><br />Using the quadratic formula, we get:<br /><br />$t = \frac{-67 \pm \sqrt{67^2 - 4(-16)(42)}}{2(-16)}$<br /><br />$t = \frac{-67 \pm \sqrt{4489 + 2688}}{-32}$<br /><br />$t = \frac{-67 \pm \sqrt{7177}}{-32}$<br /><br />$t = \frac{-67 \pm 84.7}{-32}$<br /><br />The two solutions are:<br /><br />$t_1 = \frac{-67 + 84.7}{-32} = -0.6$ (not physically meaningful since time cannot be negative)<br /><br />$t_2 = \frac{-67 - 84.7}{-32} = 4.6$<br /><br />Therefore, the object's displacement is 0 at $t = 4.6$ seconds.<br /><br />f) To find the object's maximum height, we need to find the time when the velocity is 0 and plug it into the displacement equation:<br /><br />$x(t) = -16t^2 + 67t + 42$<br /><br />$x(\frac{67}{32}) = -16(\frac{67}{32})^2 + 67(\frac{67}{32}) + 42$<br /><br />$x(\frac{67}{32}) = -71.40625 + 141.09375 + 42$<br /><br />$x(\frac{67}{32}) = 111.6875$<br /><br />Therefore, the object's maximum height is 111.6875 feet.
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