Question

4 the table shows the motion data for two objects during two trials of an investigation.
motion investigation data

object	trial	distance traveled (m)	time (s)
1	2	1,000	50
2	1	30	15
2	2	20	10

which object travels at the greater average speed?
a. object 1, because it travels a greater distance per unit of time.
b. object 1, because it travels the longest amount of time.
c. object 2, because it travels the shortest amount of time.
d. object 2, because it travels the shortest distance per unit of time.
5 read the scenario and answer question #5 below.
marine biologists are studying the speed of different ocean currents. they release gps - equipped buoys and track their movement over time. here are their results:
gulf stream: 32 kilometers in 8 hours
kuroshio current: 45 kilometers in 6 hours
antarctic circumpolar current: 20 kilometers in 4 hours
calculate the average speed of each current in kilometers per hour. which current is the fastest?
gulf stream:
kuroshio current:
antarctic circumpolar current:
the ____________ is the fastest.

Explanation:

Step1: Calculate average speed of Object 1

The formula for average speed $v=\frac{d}{t}$. For Object 1, in trial 1, $d_1 = 500$m and $t_1=40$s, in trial 2, $d_2 = 1000$m and $t_2 = 50$s. The total distance $D_1=d_1 + d_2=500 + 1000=1500$m, and the total time $T_1=t_1 + t_2=40+50 = 90$s. So the average - speed $v_1=\frac{D_1}{T_1}=\frac{1500}{90}=\frac{50}{3}\approx16.67$m/s.

Step2: Calculate average speed of Object 2

For Object 2, in trial 1, $d_3 = 30$m and $t_3=15$s, in trial 2, $d_4 = 20$m and $t_4 = 10$s. The total distance $D_2=d_3 + d_4=30 + 20=50$m, and the total time $T_2=t_3 + t_4=15 + 10=25$s. So the average - speed $v_2=\frac{D_2}{T_2}=\frac{50}{25}=2$m/s.
Since $v_1>v_2$, Object 1 has a greater average speed.

Step3: Calculate speed of Gulf Stream

Using the formula $v=\frac{d}{t}$, for the Gulf Stream, $d = 32$km and $t = 8$h, so $v_{Gulf}=\frac{32}{8}=4$km/h.

Step4: Calculate speed of Kuroshio Current

For the Kuroshio Current, $d = 45$km and $t = 6$h, so $v_{Kuroshio}=\frac{45}{6}=7.5$km/h.

Step5: Calculate speed of Antarctic Circumpolar Current

For the Antarctic Circumpolar Current, $d = 20$km and $t = 4$h, so $v_{Antarctic}=\frac{20}{4}=5$km/h.

Since $7.5>5>4$, the Kuroshio Current is the fastest.

Answer:

For the first question: A. Object 1, because it travels a greater distance per unit of time.
For the second question:
Gulf Stream: 4 km/h
Kuroshio Current: 7.5 km/h
Antarctic Circumpolar Current: 5 km/h
The Kuroshio Current is the fastest.