Question

26/ Only calculate the speed of the segment A, B, C

suddenly you sawa s later you heard the air is about 340 m/s us system can prop- stimate the time it Time, t (s) ur finger touches a FIGURE 2-25 Problem 23 per hour s tortoise, which r 1.2 minutes the flight in the same hat was the aver- val? 24. . The position of a particle as a function of time is given by x (-5 m/s)t + (3 m/s)2. (a) Plot x versus t for t-0 to t -2s. (b) Find the average velocity of the particle from t-o 1s tot1s. (c) Find the average speed from t Oto 25. . . The position of a particle as a function of time is given by x = (6 m/s)t + (-2 m/s2)t2. (a) Plot x versus t for t s 0 to p into a car and speed must you e 24 km is to be t 2s. (b) Find the average velocity of the particle from to 1-1 s. (c) Find the average speed from t-O to t-1 s. 26IP A tennis player moves back and forth along the baseline while waiting for her opponent to serve, producing the position- versus-time graph shown in Figure 2-26. (a) Without performing a calculation, indicate on which of the segments of the graph, A, ners, who are og starts run- log runs with B, or C, the player has the greatest speed. Calculate the player's speed for (b) segment A, (c) segment B, and (d) segment C, a show that your results yerify your answers to part (a). a speed of wners meet? 13 m/s utes, then peed 25.0 . (b) Ver- ed. 2 Time,t (s) t 12 m/s finally osition- ▲ FIGURE 2-26 Problem 26 d from 27. On your wedding day you leave for the church 30.0 min- calcu utes before the ceremony is to begin, which should be plenty of time since the church is only 10.0 miles away. On the way, how- ever, you have to make an unanticipated stop for construction work on the road. As a result, your average speed for the first 15 minutes is only 5.0 mi/h. What average speed do you need for , then n. (b)

Answer 1

Speed is just the slope of the position vs time graph. The steeper is the slope, the higher is the speed. Since the segment B has the steepest slope, it has the highest speed.

To calculate the speed of each, we will calculate the slope of these segments

a) Speed of segment A is

$v_A=\frac{3-1}{2-0}=2/2=1\,\,m/s$

b) Speed of segment B is

$v_B=\frac{\Delta x}{\Delta t}=\frac{3-1}{3-2}=2/1=2\,\,m/s$

c) Speed of segment C is

$v_C=\frac{\Delta x}{\Delta t}=\frac{3-2}{5-3}=1/2=0.5\,\,m/s$