Question

mission kc3: speed and velocity
a football coach starts at the 35 - yard line (a) and walks to the 15 - yard line (b). he turns around and walks to the 40 - yard line (c). he turns around again and walks back to the 0 - yard line (d). he turns around once more and walks back to the 25 - yard line (e), thus completing his 10 minutes of pacing. the coachs average speed is
a. 0.5 y/min, east
b. 0.5 y/min, west
c. 0.5 y/min
d. 1.0 y/min, east
e. 1.0 y/min, west
f. 1.0 y/min
g. 3.5 y/min, east
h. 3.5 y/min, west
i. 3.5 y/min
j. 4.0 y/min, east
k. 4.0 y/min, west
l. 4.0 y/min
m. 11.0 y/min, east
n. 11.0 y/min, west
o. 11.0 y/min
p. none of these

Explanation:

Step1: Calculate total distance

Distance from A(35) to B(15) is $|35 - 15|=20$ yards.
Distance from B(15) to C(40) is $|40 - 15| = 25$ yards.
Distance from C(40) to D(0) is $|40-0|=40$ yards.
Distance from D(0) to E(25) is $|25 - 0|=25$ yards.
Total distance $d=20 + 25+40 + 25=110$ yards.

Step2: Calculate average speed

Average speed formula is $v=\frac{d}{t}$. Given $t = 10$ minutes.
$v=\frac{110}{10}=11.0$ y/min. Speed is a scalar quantity, has no direction.

Answer:

o. 11.0 y/min