Question

(numbers 14-15) Answer the questions based on the position vs time graph shown. 14. At which time is the object slowing down? a) 0.5 s b) 1.5 s c) 2.5 s Ф3.5 s e) 4.5 s + 2 1.2 3 y 5 (sec) 2 AM a70 -90whatísthe averagespeedfor thefull5-secondtime interval? .cs0mhatistheaveragespeedfortheful15-secondtimenterval- 1 7, 38 b) 0.5 m/s 1.0 m/s d) 1.5 m/s e) 2.0 m/s

Answer 1

14. The double derivative of the graph will tell whether the object is slowing down or not, positive means the object is speeding up, whereas negative implies that the object is slowing down. Therefore positive means positive acceleration and negative means decceleration. Hence the object is slowing down at 3.5 seconds (There acceleration is negative)

15. The average speed will be given by,

$v = \frac{\text{Final position} - \text{initial position}}{t_f - t_i} = \frac{0-1}{5-0} = -0.2 \, m/s$