An object is moving along a horizontal path with its position modeled by the equation X(1) = t - 2t- - 3t, where position is measured in meters and time in seconds. What is its velocity(1 )and accelerationa (1)? O v (t) = -2t - 3 and a(t) = -2 o v(t) = 3t2 and a(t) = 6t - 2 ov(t) = 312 - 4t - 3 and a(t) = 6t - 4 O v (t) = 6t - 2 and a (t) = 312 - 21 - 3For f (x) = 2x - x + 1, describe the concavity of f (x). o f(x) is concave up for X and has no concavity at X = o f(x) is concave down for X 6 and has no concavity at X = o f (x) is concave up for X and has no concavity at X = o f (x) is concave down for X 6 and has no concavity at X =If an object's position is described by (170') = i,'3 + I2 where d is distance (meters) and t is time (seconds). Which of the following describe the behavior of d"(.)? 0 d" (if) is always negative. O 61"") is positive when (1'0) is concave up! > % and d') is negative when d()is concave down I % 0 duo!) is always positive. Which of the following are true? O f (x) has no concavity when f "(x) = 0. O f (x) has no concavity when f '(x) = 0. O f (x) has no concavity when f (x) = 0. O f (x) has no concavity when f '(x) = 0 and f "(x) > 0. For f(x) shown below, which of the following graphs is f "(x)? 48- 32 1.5 -16 1.5 -3.2 -48 4.8- 32- O -3 -2 abbin Namoo 1.6+ -1 1 2 O -3 -1.5 -1.6- 1.5 3.2 48 18. 3.2 148 3.2 O 116 -3 -1.5 -16- 1.5 O -3 -1.5 1.5 -32 -16- -48 3.2 48+