Question

In a football game, one team kicks off to the other. At the moment the receiver catches the ball, he is 40 yards from the nearest tackler. The receiver runs left to right at a speed of 10 yards per second (10 y/s). The tackler runs right to left at a speed of 6 yards per second.
How long does it take before they collide? _____

How far does the receiver go? _____________________

Answer 1

The answer is hopefully if i'm correct is 5 or 6 seconds 

Answer 2

Answer:

Part a)

$\delta t = 2.5 s$

Part b)

$d = 25 yards$

Explanation:

Speed of the receiver is 10 yards per second towards right

Speed of the tackler is 6 yards per second towards left

So here we have net relative speed of the two towards each other is given as

$v_{12} = v_1 - v_2$

$v_{12} = 10 - (-6) = 16 yards/s$

now we know that the distance between receiver and tackler initially is 40 Yards

Part a)

so the time taken by two to collide is given as

$\delta t = \frac{\Delta x}{v}$

$\delta t = \frac{40}{16}$

$\delta t = 2.5 s$

Part b)

Distance moved by the receiver in t = 2.5 s

$d = vt$

$d = 10 (2.5)$

$d = 25 yards$