SOLUTION: You and a friend are 400 m away from school, walking together toward home at a speed of 1.9 m/s. Suddenly, you remember that you remember that you need to bring your physics binder
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Question 933777: You and a friend are 400 m away from school, walking together toward home at a speed of 1.9 m/s. Suddenly, you remember that you remember that you need to bring your physics binder! You turn around and run (with a speed of 4.2 m/s) back to school, while you friend continues to walk. Then, you run back toward your friend to catch back up. How long are you running (total) before you catch back up with your friend? Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! You run back to school at 4.2m/s
distance = 400 m
time taken by you to reach school = 400/4.2= 95.2 seconds
during that time your friend is walking at 1.9 m/s
so he has walked ahead 1.9*95.2=180.9 m
when you are at school he is 400 + 181 = 581 m ahead of you
catch time = catchup distance /catch up rate
581/(4.2-19)
581/2.3= 252.6 sec
so you run 95.2 sec + 252.6 sec
=
