Tugas Kinematika Dinamika 1

2/120. Two cars travel at constant speeds through a curved portion of highway. If the front ends of both cars cross line CC at the same instant, and each driver minimizes his or her time in the curve, determine the distance d which the second car has yet to go along its own path to reach line DD at the instant the first car reaches there. The maximum horizontal acceleration for car A is 0.60g and that for car B is 0.76g. Which car crosses line DD first?

2/121. The fi gure shows a portion of a plate cam used in the design of a control mechanism. The motion of pin P in the fi xed slot of the plate cam is controlled by the vertical guide A, which travels horizontally at a constant speed of 6 in. /sec over the central sinusoidal portion of the slot. Determine the normal component of acceleration when the pin is at the position x = 2 in.

2/122. A football player releases a ball with the initial conditions shown in the figure. Determine the radius of curvature of the trajectory at times t = 0.8 sec and t = 1.5 sec, where t = 0 is the time of release from the quarterback's hand. For each case, compute the time rate of change of the speed.

2/123. During a short interval the slotted guides are designedto move according to x = 16 12t + 4t2 andy = 2 + 15t 3t2, where x and y are in millimetersand t is in seconds. At the instant when t = 2 s,determine the radius of curvature of the path ofthe constrained pin P.

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2/134 The motion of the sliding block P in the rotating radial slot is controlled by the power screw as shown. For the instant represented, 

$\dot{\theta }=0.1rad/s,\ddot{\theta }=-0.4rad/s^2,$ and r = 300 mm. Also, the screw turns at a constant speed giving $\dot{r}=40mm/s.$ For this instant, determine the magnitudes of the velocity v and acceleration a of P.

2/138 A particle moving along a plane curve has a position vector r, a velocity v, and acceleration a. Unit vectors in the r- and teta directions are e, and e, respectively, and both

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