Example applications problem

From Chapter 1

What you need to know:

Distance (d) = 1/2 x Acceleration (a) x Time (t)2+ Initial Velocity (vi) x time (t). 

Velocity is a x t. 

1. Dogs Fideaux (a Greyhound) and Wrecks (a Siberian Husky) both head for a bone at the same time. The bone is located 100 meters in front of Fideaux. Greyhounds can accelerate twice as fast as Huskies. If Wrecks is sitting 50 meters in front of Fideaux and can accelerate at 1 meter per second per second, who will get the bone, assuming both dogs accelerate as fast as they can until they reach the bone? How fast is each dog going when he reaches the bone? 

2. While Greyhounds are fast, Huskies can run for hours. Assuming Fideaux gets the bone and keeps running at the same speed for one minute before stopping to rest, how long will it take Wrecks to catch up with him and win the bone back, assuming he also runs at the speed he reached at the bone? 

1. Tie, Fideaux 20 m/s, Wrecks 10 m/s; 

2. Two minutes 

Guide to Answers

Fideaux time = √(100/(1/2 x 2)) = 10 sec; Wrecks time = √(50/(1/2 x 1)) = 10 sec. It's a tie! 

Velocity is a x t. For Fideaux, v = 2 x 10 = 20 m/s; for Wrecks, v = 1 x 10 = 10 m/s. 

Fideaux distance = 20 m/s x 60 sec = 1200 m. Wrecks can run 1200 m in = 1200/10 = 120 sec or two minutes.